BobS
Unless there are some extraordinary circumstances with his personal finances, this is a no-brainer. He should walk away. But first, do everything he can to build his liquidity as his credit standing will crash and he will have to be on a cash basis for several years. Not a bad thing, actually.
I’d also inform the lender(s) of the realities of his situation–perhaps they will see his point of view and work out a less-damaging outcome for all concerned, but that’s not likely.
