Your cat sounds like one my mother-in-law had.
Big male tiger---would disappear for a week or so,come home,eat,sleep for 24 hours(behind the old stove),and off he'd go again.
He always came home with some type of injury but survived quite a few years.
can't kill Alpo. I figured that he had a short life span when he decided to mix it up with the neighbor's pit bull. Two weeks later I saw firsthane how he had cowed the beast. the dog would actively run away from Alpo, even when Alpo was simply walking down the street.
And he sleeps in the street. he can tell if a car is going to stop or not. I've seen him stop traffic whilst he preens before getting otu of the way, slowly.
don't even think about picking him up in public!