very interesting question
I don't really want him dead, but if I had to pick, I'd say beaten to death, by the infamous florida girls or larry brown shooting him inhead, but execution style. You know Isiah on knees and with barrel of gun in his mouth and has to look larry brown in eyes as he pulls trigger.
or my personal entry would be to tie him up, piss on him then electocute him slowly. Not like an electric chair, where he'd be dead at the flip of the switch, but just enough juice to put him in pain for long enough that his body slowly cooks until he'd dead as he's repeatedly punched in face as Saunders plucks his pubes with a tweezer 1 by one.
But as we've seen you can't kill the devil that easily.