Relationship between Warren and Jimmy Buffet?

I was drinking with some friends tonight and one of the guys made the claim that Jimmy is Warren Buffet’s brother. I have never heard that. I am quite skeptical, but since I realize that I don’t know every-damn-thing, I’m turning to the dopers for the straight dope.

I believe Jimmy Buffet is Warren Buffet’s nephew.

They’re not brothers. Googling produces a few websites that claim they’re cousins (distant).