I Need Some Advice

My babyfather doesn’t like my mother over a situation that happened last year when my son was born sept baby !!! I’ve been trying to talk to him about it but he just won’t listen so he’s stuck in his ways .... so my baby is in North Carolina with his dad at the moment... so when I call an talk to my son everything is fine but as soon as my mother gets on the phone to see baby my baby father waits until we hangs up an then text or calls me an say I don’t want that b**** around my son or you won’t see him again ... like what am I suppose to do am I suppose to play it cool until my baby comes back or what like idk ... I just want everything to be fine between him an my mom my mother doesn’t have a problem with him anymore she let all the negativity GO!! It’s my babyfather like uuugghh please someone shoot me some advice !!!