advice please

Arianne
I need opinions on this subject. I do not want my sister-in-law in my baby's life whatsoever. She is a toxic person to my life and my fiancé's life. My fiancé understands why I don't want her to meet our baby, but he doesn't want to disappoint his parents and the rest of his family because they are all very close. 
Some reasons why I do not think she should meet the baby:
1. She does not take good care of her own children. 
2. She calls her two year old a douche bag, fucker, etc. when he misbehaves. 
3. She is on her phone 24/7 instead of trying to spend anytime with her kids. 
4. She steals from me as well as the rest of the family. 
5. She is a compulsive liar. 
I do not see any reason for her to meet my baby or have any part in the life of my child, but the is my fiance's brother's wife. All and all I do not think that the opinions of the family should decide who we allow in our baby's life.