Thanksgiving drama...

Well, we went to my Mom's and made it through 15 minutes before Andy made a joke and my Mom took it the wrong way. It hurt his feelings when she snapped at him, he walked outside, I came back in after going to check on him and my Mom and I got into it. I walked back outside and told Andy to go get our stuff and that we were leaving. He walked in to try and let her know that he was just making a joke and that he didn't mean anything by it and she kept going saying that he's being sarcastic and she doesn't like sarcasm. I started walking stuff outside to our van and he brought the rest of the stuff out apologizing that if he would have known that he was going to start something he would have kept his mouth shut. I walked back inside to tell her good-bye and she blew up at me and said that I'm always sticking up for him. I told her "you're my Mom, I love you, but he's my husband and I love him too and he didn't mean anything by it." She just looked at me and said "well, good-bye." I turned around and left. I cried all the way to Wal-mart to go get some stuff to try to salvage Thanksgiving for the kids. We're all starving...not the Thanksgiving dinner we planned on having today...but I think we're just destined to spend the holidays with just our family from now on. This makes 2 out of 3 Thanksgivings that the day has turned out badly with them fighting. Andy feels like he can't say anything around her anymore and that she just doesn't like him. Then she comes over and gets upset because he's too quiet and won't say anything around her. I don't know how to make her see that is just his humour and it's all innocent. I don't know he's still all in shock about what happened and feels bad and I feel stuck in the middle and really don't know what to do.