What's Really going on with my ex and bff? Hmmm

This has been bugging me. So I'm 37 weeks pregnant and no longer with the dad, whom I met through my best friend and her current boyfriend, which is my ex boyfriend bestfriend. My ex bf has not been involved with the pregnancy at all, he just lies said he going to do this and that and never follows through. so I'm over it. He said he's be there at the birth. So I'm like whatever ok. We never really talk on the phone about our son on the way and we're not FB friends. So now comes my Hummm moment. My bestfriend always calls me and have I spoke to him, did I see what he posted on FB, girl look what he posted on FB, Look what he commented on her bf page and she's leave a mad emoji under my ex comment. She even went as far as inboxing him saying he's a deadbeat dad and other stuff with saying nothing to me first. She keeps telling me, girl don't take him back if ask, don't let him see your son and put him on child support ASAP. For the pass 8 months she's been like this. On his end, he wonders and ask his friend, why your girl don't like me? He comes over to their house to chill etc. and my friend will call me hours later after he's gone that he was over there and what happened. Mind you he never stops by my house to check on me and live around from her. My ex acts like he likes her sometines too. I think before I became pregnant and when everybody was cool, this wasn't happened, my ex and bff was always on each other FB page like each other stuff and calling each other sis and bro. He was on her page more than mines. Side note; I never bring up my ex in convo to her or ask her about him nor do I care to. I just want to hace my baby and be happy. So what are your thoughts moms? Cause this sounds fishie to me. And I have not called my ex or bff out on it yet. I just hate drama...