If you don't have a Power of Attorney, someone will have to be appointed guardian or conservator in order to manage your affairs.
This can be a costly and contentious proceeding.
The New York Times has a great article today on problems in the guardian and conservator systems. They cite a lack of supervision by the courts and abuse by the guardians.
The best way to avoid these issues is to have a Power of Attorney and a Health Care Proxy that designates who your choice of Guardian or Conservator would be.
Plan in advance or you will waste money and cause a lot of suffering for your family.