Boris is the deceased great-uncle of Homer Simpson.
History[]

Boris's old country house
Homer tells his family his Great-Uncle Boris just died and left them in his old country house which is said to be haunted. Homer wants to prove this wrong by spending the weekend there.
Behind the Laughter[]
A great-uncle (or granduncle) is the uncle of one's mother or father.
Boris does not appear on the Simpsons Family Tree in "The Simpsons Uncensored Family Album".
Episode Appearances[]
Episode – "Homer Loves Flanders" (mentioned)