Advice for a friend

my best friend had an extremely rough breakup in 2018. They had been together for 4 years, but it was on and off and quite toxic. My friend was the one who got broken up with and she got really depressed. The break up happened in december so it basically took all of 2019 to heal from it.

Towards the end of the year she was doing so much better, she was about to start a new chapter in her career and i felt it was the perfect time for her to have a fresh start. Well a certain event transpired and they lead to talking a little bit and eventually decided to try again even though i was really against it she obviously makes her own choices. To no surprise it didn’t work after two months. It’s been a couple months since then and i know she’s still working on those issues, and she’s also have trouble adjusting to work life. She finally told me she was feeling better and moving on.

She doesn’t have social media, but i still follow the ex because we were friends before they started dating, but he does have a new gf. I’m not sure if I should mention it to her because she is doing better and i don’t want her to lose any of her progress. Another close friend to her was the one who suggested to me that we should say something. What do y’all think?

Update: Thanks everyone, I will talk to my other friend about just not saying anything and minding our business about the ex.