I talked to the guy - seems like a neglected car, but obviously hard to know without inspecting more closely. Can't find source of parasitic drain (assuming he is correct that it's not charging system or battery itself) -- so he's giving up, just wants it gone.
I'm tempted by it, but fear bigger issue.
If someone is local and willing to take a look for me, let me know and I'll toss you a few bucks.