I am a first-year doctoral student who works at an elementary school six hours a day and I also have two children. Sometimes I have to sit the whole night studying for a due paper or post. I need some advice as to how to balance life with work and school, and also receive enough sleep?
I'll be thankful.

There's always going to be a trade off when juggling work and study, I'm afraid. Unfortunately your job isn't of the sort where one can use flexibility to your advantage (e.g. take annual leave

Can you outsource (either to a partner/family member or paying someone) any domestic duties you have responsibility for to buy yourself some more time? Can you get ahead during school holidays so as to ease the pressure during term time? Does your commute allow you time to read or at least think ahead for whatever you need to achieve that evening?

Do build into your schedule time for rest and at least one evening off per week. If you keep at it all the time eventually you become less effective unless you have a break from it.

Like HazyJane advised, the best bet will be to outsource either asking family members to support. I have two kids and currently in my third year.
It has not been easy even though my husband is hands-on.
Good luck.
You can do it.

There are no easy answers to this.
There are only so many hours in the day.
Finding balance is about understanding you cant have it all when you have so many things you want to be good at.
Priorities have to be set and sacrifices have to be made.
For me, I put work first and family second. Fortunately I have a spouse who wanted the exact opposite. Without her, there would have been serious problems. I didnt neglect my family but I sacrificed the things I wasnt remotely interested in like helping with homework, going to school events, reading stories (UGH!) etc. Instead, we all went and spent the entire weekend doing things together and had cake, tea and film nights during the week. I discovered I had a great talent for putting on sock puppet and shadow puppets shows. Turns out that kids need their parents a lot less than we believe.

First of all don't give up. Second, you will have to sacrifice something I guess. By the way did you ever tried to get additional assistance on your academic studies, I mean professionals who would help you?

Thank you so much for all your kind messages! You gave me a strong mental support. Unfortunately, my spouse is not so flexible and believes that family should be my first priority. He wasn't happy with my decision to start studying at the doctoral level and believed it would end in my neglecting my twelve-year-old who is in a sensitive age and needs attention and control. That makes my job harder. Whenever I study during a weekend, he gets nervous and thinks I do not pay attention to them. I am very successful in my studies and do not want to give up. Just doing my best to make a balance between everything!

You should consider divorcing your husband.
I'm only partly joking about that because I can't for the life of me understand why women allow men to get away with this sort of attitude in 2016 and why men persist with it. It diminishes both sexes. Just say No!
I can't print what I think of his attitude because I'll probably get banned from the site.
Suffice to say both my daughters have been repeatedly warned to identify controlling men like this and avoid them like the plague. If my son treated any girlfriend or wife like this he would be spending Christmas alone to teach him a lesson.

BTW having brought up three children to adulthood I can assure you that a parent's influence on a 12 year old child is next to zero so you should relax a little over that. A 12 year old doesn't need "control" and needs less attention than either parents or the child thinks. On the contrary, at 12 years old the child should be encouraged to start spreading their wings, gaining a little more independence and be controlled less.
If you start controlling them at a time in their lives when they naturally want to progress to adulthood then you are going to have 6 years of utter hell coming.

You have made the most important move here by standing up for yourself and taking on the PhD in the first place. It's time for you to start becoming a bit more vocal with your husband in my opinion. It's time for him to become more of a man and start helping you out around the house to allow you space to succeed in your life. If everything has to revolve around him then I don't see how you can be happy with that. As I said, I would cosider divorce.

Thank you so much for your compassionate response! I will try to act according to your advice, but please also be aware that my husband does it out of his strong love for the kids and his constant worries for their future. He doesn't want to be selfish and helps me when he is home, but his job is a way that he has to be mostly out of home, so he says if both of us be inconsiderate of the children, they may become lazy and not progress as successfully as they should. That is what makes the situation complicated for me. He is a devoted father and puts children as priority in life. The difference is in our views about ways that children will succeed,

Sounds like manipulation to me: a nice guilt trip. What are you supposed to do, wait until they leave home? But maybe they need your support in case they need anything whilst they are at uni, so no PhD for you then. And then they might have kids of their own and then your time will be allocated for that and it may just go on forever...

Yeah I have to agree with this. It sounds depressingly like manipulation.
Bah is also defending him in a way that suggests denial so at this point I will walk away from the discussion because there is literally nothing I can think of doing to help people who get themselves into this situation. My previous advice stands. There is nothing complicated about this situation. A dominant husband is putting his own career before his wife's and is guilting her out with tales of woe about the effect on her kids if she goes against his wishes. In 2016! Unbelievable. I would never treat my wife this way and if I was THAT worried about my kids I would at least consider walking away from my own job.

This is an absolutely new idea to me. I had never looked at it from this angle. He had suggested that he can leave his job and stay home if I really insist on my studies, but I was worried about our expenses. He earns the better income for the family. I was worried about my tuition, as well, if he stayed home! Plus, I would feel guilty for exploiting him if he would do so! I don't know. This looks like a paradox to me. Where is the limit of selfishness and self-devotion?

My two pence of advice: there is no rule, but there is what works for you and your family. From what you describe it appears that your relationship is imbalanced in his favor. There are many relationships like this and ultimately, if you are both happy with your arrangements it shouldn't be an issue for anybody else.

The point though is that you feel under pressure and find difficult to cope with the current workload. So, I think that you need to talk frankly with your husband about why your study is so important to you and find common grounds on which you can re-calibrate your relationship in a way that works better for you and is fair to both.

It is possible that your husband feels threatened by your newly acquired independence and the fact that you are going to spend more time away from the family. We can discuss forever whether this is right or wrong - we don't know anything about them! - the only thing that will lead to a balanced solution is dialogue.

It doesn't sound like manipulation or guilt trip to me. Just sounds like different expectations, which need to be talked about and managed.

I'm a little confused here.

In an earlier post you said "Unfortunately, my spouse is not so flexible and believes that family should be my first priority. He wasn't happy with my decision to start studying at the doctoral level."

Your post above now indicates he has suggested quitting his job for your studies.

Has he changed his mind? If so that's great.

Either way, this can only be resolved between you and your husband and if you are BOTH happy about the arrangement then that is your affair.

In my opinion there is no good reason why both you and your husband can't get something out of this. You should be able to have your studies and he can keep his job.
You will simply need to find a place where you can both have this. The 12 year old child confuses me as well. At that age it doesn't need someone to give up their job. They should be pretty independent at that age as I've said before. They can see plenty of you at night and at the weekend but this needs to be your call.

As a final point I will say this. If your husband insists that you have to sacrifice for your child then I don't see any solution for you at all with regards your studies. If either of you are insistent that a 12 year old child needs you to give up your job then there is no solution either.
In the above situation, I would say you will simply need to wait until your child reaches an age where you believe he can look after himself. You'd need to make a decision about what age that would be.

I also find it a huge challenge to balance the needs of my family and the demands of my PhD so you have my sympathy. Is your PhD part time? If so perhaps you should consider whether you might be better applying for a full time bursaried PhD and reducing your working hours. You would have to start from scratch again but you could treat it as a job which might work in better with the family.