Mom hates boyfriend.

Hey, my boyfriend (21) and I (18) have been dating for almost 9 months. We are both still living at home as we cannot afford to move out. We have always spent the most time at my house because his parents are very strict and say SO's aren't allowed in bedrooms, etc. My mom and him have always been pleasant to each other and he has always treated her with respect, but this all came to an end yesterday. While my boyfriend and I were at church yesterday, she texted me and I didn't respond for about 15 minutes and she ended up calling me as we were leaving and started swearing at me down the phone (which my boyfriend heard). Only because I didn't reply to a text about her asking me how to forward a text......Anyways, my boyfriend and I pull up outside and he says that he wants to talk her (this has become a regular thing with mom) which I objected to and he insisted on it and went to talk to her. Long story short, the conversation did not go well. He said he went to talk to her and asked what was going on and if there was a problem which she denied and he told her he meant no disrespect and was just merely concerned about the situation. This morning I talked to my mom and she said she was "horrified" by the way he spoke to her and that she "hates" him. She also said he isn't allowed at the house at all on the weekdays, and only on the weekends when she isn't here. Then she started calling him a religious nutjob because he is catholic and she "hates" them. I wanted to get other peoples opinions on the situation, and advice on how to go about the situation. Thank you!