What do i do about thiss???!!! helppp workers comp.?

my dad back in 05 sued his company because his back got messed up and stuff, so they started giving him workers comp. and with that money he would spend it on beers, and he would be working with some other guys in construction "under the book" as the lawyer lingo goes and he wasnt supposed to be doing that. well now i have proof he was drinking while on the case, and making threats to the police on a video on youtube! but i think they already closed his case and gave him a huge sum of money and now he doesnt talk to me or my brother as if he doesnt want to deal with us anymore. so now how do i go about making them take his money away? or is it just a lost cause? by the way he lives in the state of NY if it makes any difference..