It's both more and less outre than it sounds. I don't know if there was ever a specific diagnosis, but my uncle Ronald developed a pretty severe dementia in the late 1980s. There were a number of incidents, including a period where he ran away from his wife and home (in Utah) and stayed with my family in Bremerton - I was living in Bellingham at the time so faintheart knows more than me, and rechercher as well, though I can't remember if he was living there at the time.
He was back in Utah when I'd heard that he'd divorced my aunt Marge and apparently taken up with a younger woman. Forgive my language, I have only third- and fourth-hand knowlege of events, colored strongly by the biases of those who passed along the information. The word was this new girlfriend decided he didn't need contact with the rest of his family and whisked him away somewhere...
The last concrete thing I had heard was my mom got a call from my cousin Elden, saying that Ronald was in pretty poor health - so there must have been some point where he was remanded to someone else's care. Ronald and Marge didn't have any children together; my two cousins from that branch are step-cousins I guess, since they were Marge's children from a prior relationship. Not a particularly fecund lineage, the Ralph line. In practical terms this has meant very little warmth or contact between us. So I'm not terribly surprised that we weren't informed of Ronald's actual death.
I happened to be on the SSA website yesterday for something else, when I remembered tani_chick's suggestion for searching their death index. Interestingly enough, while SSA doesn't post it themselves (you can buy a CD of the information), several other geneologically related sites have made the data available to search. Finally remembering I wanted to look something up when I was actually in front of the computer I put his name in, and got four answers back.
Two were too young, one was a trifle too old, and the fourth looked like a pretty good match. I called my mom to verify his middle initial - F, for Francis, as he was named after my great grand mother (hurrah for gender neutral names!) - and that he was six years older than my father. So indeed, it was him - he died 14 April 2002 at the age of 86.
It's not the possibility of inheritance that brings satisfaction - as far as I know there isn't or wasn't any, fantasies of rich demented uncles burying cash in the Utah hills aside. It's just nice to know, somehow, and stop wondering.