So freaking irritated at my boyfriend

So since the beginning of our relationship he doesn't really like my mom. She has ADHD and is a bit all over the place, and he is the exact opposite. He doesn't really like to come to my house because then she talks to him etc. (I know, damn stupid.) She send him a message this evening because my 18th birthday is coming up and she asked if he and his mother and father could come. I know his parents and they arent really people who like to go to birthdays and parties. He asked if i could write a message for him and even before i was finished, he deleted her message of whatsapp. I was angry at him because he was being childish. My mom doesn't even understand why he is like that and she likes him for me. This is not the first time he does something like this and it pisses me off.

Other then this our relationship is good and we have been together for 1 year and 1 month today.