That is such a hard decision to have to make. I feel for you and your MIL. I don't have much experience with hospice and that situation - but I would imagine that your MIL will tell you when she is ready and that you'll just need to be supportive and understanding. She has already been through so much. Maybe you can get a pastor, priest or other religious person involved if she partakes in any religion. They have dealth extensively with it. You could make the call to the person she'd be comfortable with and explain the situation. Usually they can take it from there. I don't think they suggest hospice or anything but they help to counsel the patient and might help her to come to peace with herself on what she wants to do.