Original: John Belushi's life is detailed in the 1985 biography Wired: The Short Life and Fast Times of John Belushi by Bob Woodward. Many friends and relatives of Belushi, including his wife Judy, Dan Aykroyd and James Belushi, agreed to be interviewed at length for the book, but later felt the final product was exploitative and not representative of the John Belushi they knew.
Simplified: His brother is James Belushi, who is also an actor.