It would be better to take it to court , if he texts you save the texts and don’t reply .
My SO is in the same situation where his babymama doesn’t want to let him see his son even tho he pays child support and has a court order that he has to get his son every other weekend. She texts him so much shit and telling him to give up his rights and so on . All that is just getting saved for court. He’s got dates of his weekends she didn’t let him get his son and so much other things
It’s better to save it than argue because he could try to flip the story and make it seem like you don’t want him to see his kid.