Mother in law nightmare!!!!!!

Holly
Right ladies I need your help, I've got a sly mother-in law and I need some advice. 
Been with my husband total 9 years, been married for almost 1, we have two sons and expecting another baby in December. Me and my husband met when I was 19 he was 20. We lived 3 hours apart at the time, I got caught pregnant very early, my husband never told his family until I told him he better make up his mind if he wanted to be a family or I raise our son on my own as I was 12 weeks. His mother butts in to everything we do, asks personal questions. If she doesn't get her own way she cries.  His mother is a nightmare when I was pregnant (before I knew the gender) she said to me "I don't think my son would want a girl" his mum CONSTANTLY goes on about "her son" "he is brilliant, he can do this, he can do that" gets my sons to constantly be about daddy, always gets the boys to write about their "daddy" never talks to my sons about their "mummy" when she was writing on a chalk board with my oldest son it was nanny, Jacob, Lucas and daddy nothing about mummy and it never Is about mummy, she is constantly trying to push me out of my own family. I also think she treats my oldest son with favouritism than my youngest as my older son looks more like his dad and the youngest looks like me. She always comments on social media saying things like "gorgeous just like daddy" maybe it's my hormones but I really need some advice.