Ive never seen the bucket list.
but I was thinking that maybe this dude could have been affected by some traumatic event that happened in the past. Hes been secluded, lost touch with his friends, family, all that junk, he has nothing and no life and he knows this. Since its his last year on earth he wants to change it so he doesnt die with regret and never really tring to "live life" he starts doing things not only for himself but, for others as well.