Maybe not -- a U.S. senator's salary is about $165K, and if his wife's salary as a nurse is about $50K (I have no idea, but it sounds right), that would make their combined income $215K -- enough to qualify for a $500K mortgage, assuming they have decent credit.
You're right, though, the other stuff is a bit more disturbing.
Maybe they still have some of the $350,000 left that she won in a malpractice suit in 1999.
The problem is the five year part for the $500K mortgage. Even assuming a 1% interest rate it still works out to over 8500 dollars a month. $215 is higher than my salary but not by all that much and there is no way I could come up with that amount of money on a monthly basis.