Should i get something for the office manager?

we have a small office being its just 2 of us plus the office manager and our boss. the 2 of us went together and got something for our boss to give him when we have our companys christmas dinner tonight and we were wondering if we should get something for the office manager and would it be weird if we didnt. he is our bosses dad and didnt know if that would make it weird not giving him something.