Back story my husband and his brother are on no terms at all due to my MIL

Please go read my MIL rant to understand why she's not on our lives.

Well my husbands brother was engaged, cheated on his fiance, and got a baby our of it who is months older than my baby. He denied that baby for 6 months. Now that he's a part of it he has instructed his BM not to let their son in our lives. Now I have spoken with the BM and she has assured me she doesn't care what he says her son deserves to know his family. I am so happy that our son has a cousin and the crazy thing is they have the same middle name lol.

My only reservation is if my MIL starts trying to start more drama (which she's not made a great impression on the BM) I'm not worried she will create drama between us and our sons cousins mom just that she's going to start harassing us and talking about my baby. At that point I will let that whole respect your elders thing go out the window. I hope I have made the right decision letting our son meet his cousin and continue a friendship with the BM.

P.s my husband brother is the one holding the grudge and things will never be resolved until my MIL is out of the picture she uses his brother as a minion.