Dont read this if this might be a trigger!!

There is an uncle (my father's bother) that desappeared in foreign lands never to be found.
My father thinks he was murdered, but he talks very little about this situation. Is like a family secret.
From what I gathered during the years he was a very/very smart, very problematic person (booze and fights). And he was my father's best friend.
My father still thinks he was murdered, but my father is very paranoid.
From my family history it is cristal clear to me, from what I have gathered, that the s** word was a factor. Coming to this conclusion is a shock to me.