Everything is a competition with my MIL

Me and my husband struggled with infertility for a while. I knew it was me not him because he had a kid from a previous relationship. He stayed with his mom and him on weekends except during his high school years and first year of college he lived with us. And great kid. We had our ups and downs and I think he's an amazing guy. He's 23 now. I finally got pregnant through <a href="https://glowing.com/glow-fertility-program">IVF</a> and not too long after, his mom got pregnant. She said she all of sudden wanted a baby again and it was so easy for her given her age. I was happy for her and happy my hubby was gonna be a big brother but she made everything a competition. She literally asked for our baby shower date so she could come and then through her baby shower the exact same day as ours. I remember that shit so well. Both my son and his little brother are the same age. Theyre a month a 3 days apart. Both 16. She makes everything a competition. And because of that his brother has become cocky. When we are over there she will ask if I think my BIL is handsome and I'll say yes and she will say "Yep, blonde hair blue eyes. No offense but your son is gonna have a competition". Our son is red hair, green eyes. His gets his red hair from my dad and green eyes from my husband. Talks about how much more good looking my bil is than our son. My brother in law plays basketball. My son does theater and she said "He might as well just go to boys because with my son he won't have a chance". And my bil bullies my son. They go to the same school. And his mom allows the bullying. He stood up to him for once and my bil punched him the face and everyone laughed and all he got was detention. My mil said "It's not my fault my son is better than your son". He's not just our son. That's her grandson. His nephew! How can she really make this all into a competition.

Edit: My husband has gotten into fights with his mom and his brother. He had even picked his brother up by the scruff of his neck when he put his hands on our son. However he won't cut his brother off because he says he's young and needs some form of guidance since his mom is doing a shit job.

Edit2: while yes he's young, 16 is plenty old enough to know not to bully and PUNCH someone. He's not 10 and can be charges as an adult for some crimes. He knows right from wrong. If he puts his hands on my son again I'm gonna tell my husband he needs to cut off contact for now because my son doesn't deserve to be abused by family. I'm not gonna put this all off on his mom because yes she's a big reason. He can make his own decisions at 16 years old.