I have to say that does not ring true. I say that even as I like and respect Tony Snow. But if this story quotes him acurately and not out of context, I think Tony just lied to us about his main motivation to leave. I don't know about that ... maybe he could handle his old mortgage, and maybe he could handle his old mortgage along with rent on his DC digs... But if you pile on some big medical bills, I'd guess that his financial obligations are eating him alive.
And maybe, just maybe, he's worried enough about his lifespan that he wants to put away a nest-egg for his kids.
Also remember several years back that Tony’s house burned down. I’m sure with the cancer treatment and that, that his big Fox paycheck was consumed pretty quickly. The White House gig was a favor to President Bush, who desperately needed a better PR man. Ari did a good job, but after that things backslid in front of the cameras.