I'm surprised that there can still be bad feelings between christians, especially since the different churches have actually got really good at networking - visiting each other, days out, advertising others' services etc. It's always individuals who have misinterpreted the messages that spoil things! The whole point seems to go right over their heads.
H, I love your passion AND the fact that your mum prays in other churches. There's something about any sacred place of worship, in my experience, that brings calm into my life. I spent a good few years 'lapsed', but with my own thoughts and spirituality. Now I do go to mass somewhere where I feel comfortable and the priest challenges my thoughts. He makes a point of not excluding people and welcomes unfamiliar faces.