Oh dear....yeah, she's used to it, grew up with it. My first MIL used to drive me batty telling me how to mother and raise my kids. She also totally interfered in how I was decorating my first house. She was a control freak and was always correcting me. I remember being at work and her calling me to tell me she had let herself into our just newly bought house to rehang my drapes because I had hung them all wrong. I calmly thanked her, hung up the phone, called my husband and screamed at him to get his mother the .... out of my house.
When I divorced him I told him I wasn't just divorcing him, I was divorcing his mother too.
But my point is, he never understood why I let her bother me. He had grown up with her controlling ways and he just ignored her. I was raised to respect elders; I was 20 years old and thought I had to listen to her.