My MiL objected to us getting engaged - apparently she wanted to choose if and when her son got engaged (we still got engaged when we wanted to and she then tried damage limitation!).
Since then, I've weathered lots of rude comments that were played as 'misinterpreted' or 'inadvertently rude'. I could write a book about the things she has said to try to drive a wedge between us. She made cloaked comments about me keeping her son from her, when in realistically we went to see her when I said, 'Don't you think we should see your parents this weekend?' we used to go to see them at least once a month, sometimes every 3 weeks, almost always together and then with the children. They rarely came to see us - literally 3 or 4 times in 30 years.
I've only ever been seen by her as an inconvenience. She knows nothing about me.....because she's never asked!
A couple of years ago, as our children needed ferrying around at the weekend to get to their work, and my Mum needed more support, he started going on his own. Honestly, she's happier and I am too! I never stop him from going or telling I don't want him to - I just don't want to go either.
I see her on her birthday and that's it.
...he still only goes out of duty, though!
It would only have ever taken her to be pleasant to me for me to think completely differently of her. Be careful how you treat those in your son's life, because there are there because he wants them to be and he values them.