Sorry for your loss. You're a lucky man to have had a friend like that. That kind of friendship is hard to come by.
I too have a friend from all the way back to jr. high. Been close friends for about 44 years now and would be crushed if something happened to him. That subject has come up from time to time and, put it this way, he's the ONLY person I would trust to take care of my dog if something happens.