How long is he expected to live?

My aunt in Montreal has a cat, his name is Bandit. This cat was bron in 1998, he is now 11 years old which is equivalent to a 65 year old person. (In Korea they would call him a Hwangap cat). My mother gave her and her husband one of the kittens who was born last summer, and that young cat is so active that old Bandit does not want to play because the old cat is retired. My question is, how many years is the old cat expected to live?