I'm sorry for your loss Dave. I went through the exact same thing with my mom almost 14 years ago. Experimental drugs, Hospice at home and then we moved her to the Hospice house. Things will get easier as time passes. I'm glad you had the opportunity to spend time with her. I'm still thankful for the awesome folks who work with Hospice.
Spend time with your Dad and celebrate the life of your mother with him.
