I need to be my 86-year-old mother's legal caregiver. How do I go about doing this?

Contact a elder law attorney and they will be able to walk you through it all and make sure there is the proper paperwork. You will want to have POA for her medical and financial when and if needed. And then get your hands on all the info you can about the needs your grandmother might need and make sure your up to the job! It can be very demanding caring for someone 24/7. I care for my husbands 98 year old grandmother with alzheimers, diabetes and blood pressure problems. I looked up as much info and all her conditions and learned so much more then I thought I did. And talking to other caregivers dealing with the same kind of things really helps. And when the road gets a bit tough its nice to know you have a place to vet and ask questions and the answers are coming from someone who's walking in your shoes. Good luck to you and take good care of mom!