Am I just being that Mom?

My sis in law and I have babies 2 weeks apart. Her baby is the favorite always being held always being the one they buy for while my daughter is ignored they’ve bought bags of toys and clothes for him and only a few clothes for my daughter and not one toy for my daughter. Today we were at my mother in laws house and he tackled my daughter to the ground, she didn’t cry just got out from under him and tried to go on her way and he grabbed her and bit her on the head. She started crying and my mother in law was like oh I don’t think he hurt her to bad. Later he fell and hit his head and she went on and on about how bad it was. The thing is this happens all the time. He hurts her and she starts crying and my mother in law is like oh your fine he barely touched you He has literally left teeth marks on her for days. He’s little enough (9 months) he really doesn’t know better but it really upsets me that my mother in law is just like get over it to my daughter and gushes over him. We’ve been here most of the day and she’s held my daughter once and packed him around all day. Am I being that Mom that’s overreacting and jealous or would you be upset too? He literally just hurt her again as I was typing and she was like he didn’t mean to she just cry’s alot and she hurt herself because she fell over when he landed on her.