don't have too much experience with this, did the money appear in his stars account after the check bounced?
he should definitely e-mail stars support and ask, but it might be a bit of time before they respond.
did your friend (it's gonna be funny when we find out that you're the friend, but i'll play along) withdraw money from citizens bank somehow and his account there is now negative? if that's the case, i imagine he's going to need to pay citizens bank whatever amount in the red he is (so if he had $2500 there, withdrew all of it, then the check didn't clear and he now has -$2500, he'll probably need to pay this back and whatever overdraft charges citizens bank charges).
i don't think he'll be able to get away from not having to pay citizens bank what he owes, in any case.
e-mail stars support, i'm not completely sure how this works, maybe someone else can chime in