If your boyfriend or girlfriend did this would it be rude?

My boyfriend and I have been dating for nearly 3 months now. He has come to my house several times and vice-versa.

Would you find this rude:
My mother saved a chicken sandwich for my father (dad was at work). My boyfriend just opened the fridge and freezer. He ate the sandwich without even informing us and served himself ice-cream (our ice-cream). My mother is starting to dislike him and thinks that was very rude. She's also noticing that he comes with good fancy things for himself and doesn't get me anything nor shares (just like with the ice-cream... all for himself).
If your boyfriend or girlfriend did this would it be rude?
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