I left my job at the end of February and left the USA together with my whole family. My replacement reached out to me about 1,5 weeks after I ended my employment asking questions relayed to work. All this despite the fact that I gave a 2 week notice and everyone had all the opportunities to ask any and all questions for a smooth handover. Not my f'in problem that you don't ask everything you need to.
You don't owe anything to anyone, especially when you're no longer an employee. Do what you are paid to do and nothing more.