forget mil bday .....

Idk tdy was my husband mother bday..until we went out for dinner and collect cake from her sister. my husband than say "tdy is my mom bday". We only eat at coffee shop.. and all order different types of food. Not even something that can make her feel that we are celebrating for her. Anw he was taking the cake out and wanted to cut his mother say "no,I don't want to celebrate" he told me that his mother is angry. I ask why don't he tell me if he is so forgetful. he say no point saying thing like this it not going to help at all. Say something more logistics that not just saying thing not helping. He's not blaming me.. but the way he put it in it sound like my fault.. I feel sad for not celebrating for mil. I blame myself for not asking before hand. Yes, whatever it is can't turn back the clock. But I really wish that I could and do something to make her feel better. But I have no idea what I suppose to say or do... Im so helpless.... But lastly I still wish her happy birthday.. oh thank u she said.