At
5:34 into the Oil Diffuser arrest video, Andy gives out a very important clue. Andy stumbles on his words a bit but says to Officer Bentley "tell my dad as my representative payee to get me my apartment then" - the main reason Thomas puts up with all of Andy's behavior is so he can continue to be the payee for any benefits.
If Andy gets put in "gwoup home" or "hospul", then Thomas loses access to these payments. where the state of New York would deduct these benefits to pay for Andy's direct care. Andy probably understands that his father would not get money anymore so this is why all of Andy's stays at hospitals turn out like his recent stay at Newfane, e.g refusing new medications and treatments
It very likely explains why Andy's parents never press any charges, any extended jail or prison time for Andy would mean Thomas wouldn't be allowed to be the representative payee.
In my opinion, there is more than one criminal in the Ditch family.