my babies grandma

My boyfriends mom has only seen our baby once the day after he was born. She never got us anything for him even tho she said she has, didn’t come to our baby shower and hasn’t talked to us in the 2 out of 3 months he’s been born. She’s been arrested multiple times and is on pills and other drugs. My boyfriends dad has two other children with a another women and we love her and are going to be considering her his grandma. I feel

bad for my boyfriend and my son because of the way she is i know it makes him upset but I just want what’s best for my son. I know what it’s like to not be wanted by a family member but how can you not want to be in your grandsons life?