I would say 5-10 at most. He's survived quite a bit, but the human body can only take so much punishment before it shuts down for good. I'm guessing he won't live to see 2024 probably, but it's always possible so that's why I said 5-10 more years.
That might be why he still eats from the trash... the maggots expend less energy eating pre-rotted food. It all makes sense.Jokes on you, Tom's been dead for years. His body is being animated and controlled by a colony of sentient mutant maggots and bacteria from dumpster burgers and a neverending cocktail of whatever he can get high off of.