Letting her go is the most loving thing you could do.I remember when my Dad was dying. He was in a coma. But I knew how much he wanted to be free and actually felt happy for him. He'd been suffering from depression and anxiety for a long time. Just knowing he was finally free made me happy. I never cried for him. Never needed to. If there is a next life he will be a serious spiritual seeker so how could I want more.
The important thing is that you are there while she is still in the body. Also feeling that you set her free.
I'm glad you have family to support you.
All kind and loving wishes I will send to you.