What to do?

So I have posted a couple days ago about my bfiking lingerie pics of our mutual friend on insta

Today I found out today (he toldme) that she's been dming him every time she posts a story (on insta) she'll send it to him, and let's be fully honest here since she did a lingerie photoshoot 95% of what she posts is pictures in thongs with booty out etc. And he said that he only likes those messages cuz he "doesn't know what else to do", and like I don't like this, I don't like how another girl feels good about sending my bf pictures of her ass, also she has a bf aswell which makes it worse in my opinion.

I don't know what to think about it and how to talk about it with my bf, he says he doesn't know what else to do except liking the message but I think is not that difficult to message her saying "stop messaging me those pics its disrespectful for my girlfriend" it's not like I ask him to delete her, I just think is disrespectful for her to do that... I don't know, what do you girls think?