I think its great you are reading a book to gain further insight. I have this illness as well. I can't understand that perspective exactly, but it seems to me that your mother isn't very appreciative of your efforts to help her. Maybe she feels more responsibility that she should be taking care of you, rather than the other way around. I often feel that way. My parents and husband have to help me out a lot, and I often wish I was helping them instead.
t sounds like you're doing just about everything you can. You said sometimes she goes to therapy, have you guys ever gone together? It helped me when my husband went with me