This is a totally amateur reply, I'm not in the building trades.
Offhand I'd guess anything can be saved but at a significant cost.
There's companies that do hydraulic (?) raising of foundations etc.
I'd expect it to be expensive, like in the tens of thousands of
dollars. Where I live we get these radio ads for Olsham Foundation
Repair - no clue if they are any good or if they work in your area.

You would not want to buy the house without understanding the problem,
& the cost of fixing the problem, because You Buy to Sell.