One of the semi-feral cats ("Buckley) my friend and I were re-socializing escaped from the house. Two weeks later Buckley showed up at my colony--the same location from where he was trapped nine months earlier (two miles away).
(We retrapped Buckley; he was a changed man; he has since been adopted into a Forever Home.)
Kimba, my favorite stray cause he is the most friendly (he cuddled on my lap), disappeared about two weeks ago. I think he had underlying health problems; I fear the worst.
I don't know the background of Boof, but I do know a lot of ferals/strays are only snow birds; that is, they come around regularly during the colder months because food is scarce. Once it warms up and mice and birds are more plentiful, then they disappear for a while. If Boof is sickly, then, yeah, PRAY.