MY BOYFRIENDS BABY MAMA IS A MONSTER!!

My bf is in love with his son but he dosnt see him much everyone! Says that it's his fault he doesnt try to see his son and for a while when I first met him I wondered why he didn't see his son much either he would somtimes cry becuse he knew his relationship with his son wasnt good but now 4 years later I know it's not his fault ITS HIS BABY MAMAS!! She pushes him away and then blames him for not being there it's gotten so bad that hes figured it's not even worth trying to see his son becuse his son believes his mother when she says hes gone becuse he wants to be and he a piece of crap today her and her husband called and yelled at him for not being in his life when they LIYTERALLY WILL NOT LET HIM BE!

One time he cried asking me what he could do to show Jacob he loves him and wants to be in his life I told him to start texting Jacob (age 13) everymorning or even once a week tell him goodmorning and to have a good day at school even if he wants to ignore them at least he would see that his dad is trying! That lasted about a month and then what do you know his baby mama jumps in and tells him to stop texting Jacob becuse jacob came to her and said he didn't want to talk to him

She told my bf that jacob was "smart for staying away" she feeds that kind of stuff to jacob all the time but says she doesn't I dont know how to help as EVERYONE BLAMES HIM they want to take him to court to gain full custody that way she can make medical decisions without him! What can he do?