Wonder how this is going to shake out legally for him and Joe. If she dies first then Tom becomes the sole homeowner and when he dies it's going to be split between his 4 kids, leaving Andy shit out of luck because they'll probably get together to force a sale of the house. Best case scenario for Andy would be Tom dying first, his next of kin (his wife) receives everything which leaves Andy and Joe, her only children, with 50% each. If I were Tom, knowing that Andy already tried to kill me and knowing Andy is aware that his mom is declining, this would be my biggest fear about letting him come back.
(This is based on my understanding of probate law from what my family went through when my grandmother died and her house went to her estranged, but not divorced, husband which down the road gave their shared children and his bastards equal split.)