Holy cannoli! Im afraid to drive myself very far when its too hot out, and he wants to do a 2 or 3 day drive? I know ive turned into my dad ("my home is my castle! Whats better than that?!"), but if ANYTHING happens - even if your own car is perfect, somebody else can do something stupid, and you could be stuck out on the hot road for hours. Okay, im a chicken-shyte, as my mother would say, but at least im still alive.
If you need any arguments for not going, ive got a million of 'em!