Since you are an M.D., you may want to focus on courses involving health law. I do not know what states you are interested in attending law school. University of Houston has a L.L.M. degree, which is earned after a J.D., in Health Law. I encourage you to attend in a city where you would attend law school, and then find employment after law school, in that same city. You may need to be in one of the 10 largest cities in the nation. Investigate which law schools offer a lot of health law courses, in their J.D. program. If this area of the law interests you, it will build on your experience as a doctor, and may open doors in the medical area. Houston has the 3rd largest health center in the country. Whatever state you live in, if you want to stay in that state, consider applying to the law schools in the largest cities of your state. See which law schools offer "health law" institute programs. Also, take guardianship and elder law courses, in law school.
I admire you for having the guts to go to law school at 51.