blood: thicker than water, thinner than a big wad of benjamins

From ESPN.com:

Floyd Mayweather Sr., who has trained [boxer] Oscar De La Hoya since late 2000, said it doesn't appear he'll work for De La Hoya -- and against his son -- in the May 5 super welterweight title bout [between De La Hoya and Floyd Mayweather, Jr.] [...]

"If they want me to work against my son, then they're going to have to pay me," Mayweather Sr. told the Las Vegas Review-Journal. "My son and I, no matter what's gone down between us, he's still my blood. Hey, I'd work for Oscar if the deal is right, because that's my job and boxing is just a sport.

"But if you want me to tell you how to beat my son -- and I'm the only one who can tell Oscar how to do that -- then you need to pay me."

Isn't there some pseudo-apocryphal story about George Bernard Shaw sitting next to a man in a bar and saying, "If I paid you a million pounds, would you help me beat the living hell out of your son?" And the man saying quietly, "I guess I would." Then Shaw: "What about for twenty pounds?" Man, indignant: "What kind of father do you think I am?" Shaw: "We've already established that. Now we're just haggling." (For those unfamiliar with the reference, the merely apocryphal version of this story is here).