Savings Account Responsibilite

My son & his wife are separated and he has filed for divorce,She left him and is living with another guy.SO anyways,they had a SMALL savings account with $10 or less,and she puts her pay in then takes it out later in the day or the next day or something like that.
Well, anyways A check got cashed(an other persons pay check) with HER(his wifes) signature under the owners name,ANd for SOME reason the bank(of the pay check) stopped payment on it.NOW the credit Union is trying to tell my son he is responsible .HOW can this be,SHE (his wife) signed it and put her soc.sec. number on the check as well.Since this time he has removed his name from the account,BUT at the time this all occurred his name was on the account.If he has to pay on that check it is not right.PLEASE LET me know SOON.Thank YOU

THIS IS IN THE STATE OF Virginia

[JETX]

iT Is VerY Hard TrYinG tO reAD YouR pOSt wiTH yOU DoiNG YoUR CAps KEy lIKe ThiS!!! Isn'T It???

In any case, the account was a joint account at the time of the incident. This makes EITHER account holder responsible for the actions on the account. He is liable for the loss that bank incurred. Additionally, he can sue his 'soon' to be 'ex' for his damages, the amount he had to pay on her behalf.... if he can prove that she was the cause of the 'damages'.