What's his issue

So My ex and I split up 6 months ago. Well my ex wants to remain friends which is fine with me especially since we have a child together but every time I'm around him he always brings up my best friend Who just so happens to be a male and he has even asked me if I sleep with him when I stay at his house which was a super weird question for me because why is that his business 🤷‍♀️. My ex says he doesn't want to be together which I don't want that either (he's a walking red flag lol) and says he doesn't have feelings for me either (same for me) but why does he always bring up my guy friend. More instances are where I'll be at his house (the ex) and I'll be texting my friend and he'll be like wow just ignoring me huh or he'll come up and be like who you texting.. I've even seen him roll his eyes when I'm texting and not paying attention to him but I'm only there for our child to see his dad not for me to really hang out with him. I'm thinking of just having him pick our son up from now on because it just gets weird. Also he insisted I add him back on my social media (I blocked him on everything after the break up) but I told him no that we can just text and he seems pretty annoyed by that.. He will literally text me every day and if I don't respond for a few hours or if I read it and not respond he'll text and be like you could just say you don't want to talk instead of leaving me on read or if I finally respond he'll be like damn thought you died.. It's like he's 13 or something lol.. Like wtf is wrong with this boy lol..

One more thing to add here is that he dumped me.

Also don't hate on me for trying to remain friends with him because I don't have feelings for him anymore so it wasn't a big deal to me. I know some people will judge me for that but with the way he's been acting I think I'm gonna avoid much contact with him from now on.