What can I do if my mom dies at home?

I agree. Call 9-1-1. They will know how to handle everything. Your mom is 91 and could still live a long time, but you are right to be aware that she may not. None of us lives forever. If you worry about this too much, talk to your pastor or other counselor about your fears. Take care of yourself,
Carol

Call 911 and give all the info they request. Medics will have to come out and pronounce.