Greedy State won't pay

Hi y'all! So I was talking to my dad the other day & he mentioned the state is giving him trouble about his tax check, they made him fill out a bunch of "identity info" & when he was finished they said it wasn't him! So they are trying to keep his return, I've suggested numerous ways to get around this but because he's "still sleeping" he's failed to try any. So, anyone have any suggestions as to what he may do? Appreciate any & all feedback. Peace& God Bless