Mother in law discusses me

Okay so my first son isn’t my husbands biological but my husband been his ONLY DAD since he was 1!!!!!! My mother in law says bc he isn’t blood she didn’t care for him. My husband explained to her that he is HIS son and blood couldn’t change a thing. We then got pregnant and now have a one year old! she wanted to make up with my husband but he said he didn’t want anything to do with her bc she’s always going to treat my older son unfairly and he doesn’t want to see it and he’s upset she doesn’t respect that he told her this is his son as well. She then said I was the reason he didn’t want to associate with her. I told him no matter what that was his mom and to talk to her. He said no and that he’s been much happier. she has never seen the baby who is now 1 bc my husband does t want to see her but she’s asking his sister for pictures of only the baby. I know that’s her “blood grandson” but my older son really wanted to be close with her and she just didn’t like him. He’s the cutest and his brother is identical to him. I hate feeling as if I was the reason he doesn’t talk to his mom but he completely made that choice on his own. Thoughts on this?