Social Security Check for Deceased Parent and I'm listed as OAO

My husband received a check for a portion (he has two siblings who also received a portion) of his mother's final social security check, which was paid after she passed away. He has received a SSA 1099-SM with his name listed, followed by OAO and then his mother's name followed by DECD. Is this a taxable benefit to him, and do we need to report it on our tax return?