Well, even if he was the last human on Earth, at least he's got a great family in Jake and some good friends all around and is enjoying life3nodding
Also with Betty now in the picture, Finn is not the last human now.
Also, there was one episode were Jake used his body so they can find their way around some maze & some banana guards that were there pushed him to the limit. There he was going to die, but that might be because of all the poison and stuff his body had to deal with.