Does he miss me?

When my ex dumped me, he said he hoped we could stay friends. After about a month NC, we started talking bc I asked him if it was cool if I gave a concert ticket intended for him to my friend. We got on pretty well. He always answered me right away unless he was at work(or even sometimes during) and was one of the first if not THE first to like/view my social medias. Just generally acting like he knew he messed up/missed me but didn’t want to say. Then I got an internship at our church. I messaged him about it, asking for prayer. No answer. Ok I figure I sent it super late, but he probably did. I tell him how it went. Sees it but doesn’t say anything. And is conspicuously offline-hes usually super active on Facebook, but nothing except a generic 4th of July post. So now he’s just off the grid/ignoring me.... I can’t think of anything I might have said wrong... And his sister(my bff) invites me to a big church event and makes it a point to say I might see him. Like him specifically. Which is just super weird. And she says ever since the breakup he hasn’t slept good, or eaten well, and just seems really off.

And one day I babysat his nieces(kids of aforementioned sister) and they kept saying that their uncle said he wants me to be his gf again. Which kids their ages (5 & 3) wouldn’t just say out of nowhere. They had to have heard it from somewhere....