Do I need to go to court for legal guardianship

My cousin is mentally retarded, blind & in a nursing home since my aunt died. Both his parents are deceased. He has one living relative left (his brother). I'm trying to help him (the brother) w/his funeral arrangements, etc. He's a veteran but doesn't belong to AARP. The brother is 83 & worried if he goes first, his brother will become a ward of the state. I thought he could get a legal guardian appointed without going to court. If so, how do we go about it?