Everyone should have these three basic documents, regardless of their wealth or health:
You should have your Durable Power of Attorney.This would allow your agent to pay your bills and make other time-sensitive decisions during a period of your incapacity.
You should have a Medical Power of Attorney. This would allow your agent to make medical decisions for you (in consultation with your physicians) if you were unable to make those decisions for yourself.
You should have a HIPAA authorization that authorizes your loved one to access your protected health information.