Did the IRS cash the check, i.e. did it show up as paid in your bank account? If so, then the IRS has the money. They just didn't credit it to your son's account, because of the wrong SSN. Your son has to call the IRS to straighten it out. If your son is too young to call himself, you should be able to make the call.

If they did not cash the check, stop payment on it and pay what the IRS notice says he owes.

Thanks for the reassurance, yes the IRS cashed the check in April.  We are trying to call together as he is still a teenager but an adult.

Did you put your SS# on the check ?   If so you have a credit on your account.  I would get a picture of the cancelled check, a copy of the IRS bill  & a copy of his return  and go to a local IRS office with your son to see what can be done about this situation.