Bravo to you for stepping up to take a snake that would be considered by many as "not worth the trouble". It's encouraging to know that there are always people in the world that see and value the worth of all living creatures and not just the pretty, easy, or valuable ones.

It does indeed sound like the poor snake has been through a lot. Poor husbandry and neglect, if not outright abuse.

The "wobble" is common in spiders, yes, but it can be seen in other ball pythons and may have a cause that is not genetic. In this case, it sounds very likely that some environmental issue caused some neurological damage. Too much smoke in the environment, perhaps. Or maybe the guy was not particularly careful about where he used household chemicals for cleaning or pest control or whatever. Or maybe he was cooking other...less savory...things in the area. There's no way to know.

All that said...I believe your new snake can live a perfectly happy and comfortable life if given the chance with a caring keeper, a safe and proper environment, and regular food. Sounds to me like he is in just the right place!

I wouldn't bother trying to follow up with this guy. He does sound like a scary piece of work...or maybe he's just mortally embarrassed at how badly he's cared for his animals. At least he's trying to find new homes for them and we can only hope the guy doesn't get any more. Badgering him for information he doesn't want to give, or trying to explain the error of his ways won't accomplish anything...and if he's as shady and scary as he presents himself, could put you at risk for trouble you don't need.