Is he talking to his ex ?

My bf has an ex that won’t leave him alone and We’ve been together for almost 8 months. She calls him and txt him in the middle of the night . I’ve even answered cuz he told me if I hear it go off and it’s her I can answer it . I’ve told her leave him alone multiple times but HE HIMSELF won’t tell her to leave him alone . She lives in another state so they aren’t seeing each other . Sometimes he’ll talk to her like 10-20 min like once every other week because her daughter grew up thinkn he was her dad and she wants to talk to him but at what point does that stop she can’t use that excuse to talk to him forever right ? My sister thinks they low key talk because she’s not crazy for no reason . And she has me blocked on Fb and her page private but my best friend sent me this screenshot like why is she liking this post but don’t like nothing else. And he’s sleep so I can’t ask him about it so what do I do ? Could he be talking to her ?