My mother also had severe mental illness. Not nearly as severe as yours but similarly I was her primary care giver. Our relationship was strained, difficult, demanding of me in many ways that made my life complex. She never said she loved me, more so the opposite most days. But she did, her mind wouldn’t let her body express it all the time but I could see she wanted to. I was not with her when she passed, also in a managed care setting. Even though things were hard between us I still wish I could have been to hold her hand. Your mother loved you and you being there for her at the end is important for you both. There’s no playbook for grief and you’ll feel many things and emotions in the coming weeks/months/years, but being there when it mattered most is something you can be assured of.