You can't just instantly repossess. Even with nonjudicial foreclosure (which Virginia has), you still have to set up a date for the sale, and if someone is squatting there, you still have to go through the formalities of getting rid of them. Until they foreclose, he (and Cole) would be the owners in the absence of a will, and I assume Barb is too selfish and stupid to have bothered with that.
He'd also ignore whether or not the bank now owned it and cling to it like a barnacle for however long as he could. So if they jumped in and immediately foreclosed when he showed up to claim his "birthright," if he was already there, he'd probably stubbornly refuse to leave until dragged out in Hedgehog Defensive Posture, screaming and wailing. Not sure how long that would take. In some states even a squatter who is a total stranger to the property takes months to evict.
I suspect it would go rather more quickly in Virginia but I don't really know.
Any unsecured creditors who hadn't perfected a lien on the property by that point would be shit out of luck, and probably even the ones with liens.
There's also the possibility of a reverse mortgage. That's been an urban legend that has floated around for years because of one mistaken statement by Null. That was a normal mortgage. However, she could have got one since then, if there was any equity whatsoever in the house to get one with.