Thanks
I think the best thing for you to do right now is to block the casino account and focus on a reliable casino that have a good reputation.
Check the first reply in this thread it was from a casino representative ( not the one the op is using though) and he confirmed that casinos asking for source of wealth is a thing and not just made up to chase players away and also I have seen someone else ask about the same thing - I can’t recall the thread or how they went about but the casino sure asked them to submit the source of wealth but the only difference with this one was that he was making use of crypto deposits so it became an issue for him to provide them with that information.