My Husband Has Sinus Surgery Today And He Took Hydrocodone

My husband has sinus surgery today and he took hydrocodone at 2 pm as instructed. They gave him another one at 5 pm. 10-325. He also had 2 triazolam ,25 mg prior to surgery. He is at home but when he awakens he says he I’d freeing to the point of shivering. Is this normal? Has me worried.