Welding an extension onto the driveshaft is probably the dumbest stunt I've ever heard of, or at least it's in the top 10! He will be lucky to get 5 miles before it shears off, and now he's got two ruined drivelines. Cobble-up jobs like that need to be avoided at all costs! Let him screw it up royally, then offer him about a nickel on the dollar for his pile of junk! You might get some good parts out of the deal.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!