My husband passed away and we received his social security for the month he passed do I have to pay that back?

The month he died is the first month he should not receive payment. Social Security will deduct/reverse the payment from the account it had been deposited to.

Sorry, i meant the opposite. If the check came AFTER death then yes...

Did you get the check before he died? If so, yes. If he died after, no. My dad died July 30, 1999. The deposit he rreceived in July was not refunded. The system didn't notice his death immediately so a deposit occurred the first week of August. That one was pulled out the bank when we notified SSI of his date of death.