Just need to tell someone and maybe get advise?

So my boyfriends brother has recently gotten out of a relationship and is talking to someone knew. They went to school with each other

But they both got out of relationships around the same time so it seems like they planned it 🤔

And I follow her ex on Instagram and I seen that she’s still liking all his posts and still interacting with him. When I know my boyfriends brother and know he wouldn’t be happy with that (ex’s are a no go and he has no contact with his ex and has unfollowed her on everything)

And also my boyfriend and I Are worried that she might still want her ex and because they’re both moving on so fast (even tho his relationship was over long before it was officially done) that she will get over him fast too?

He went through so much pain with his last ex, she was kinda crazy and controlled the hell out of him and now we don’t want to see him that heartbroken again

My boyfriend has said to him to wait it out before getting into another relationship. To make sure they’re both ready

Edit**

Do we tell him that she’s still in contact with her ex?