Caught in the middle of 2 friends breaking up. How do I deal with a friend who always plays the victim?

I’m part of a group of friends, and two of them, Chloe and Mason, just had a massive falling out. I talked to both of them, and they confirmed they are done. I am stressed out because our summer break is ending soon, and I'm terrified of how awkward things will be when we all have to return to our community program next month.

The fight started because Chloe didn't like a new outsider that Mason started hanging out with. Chloe felt this new person was a bad influence. Chloe made a critical comment, and Mason got super defensive. Mason basically said, "You just don't like the new version of me who is trying new hobbies and hanging out with different crowds." Chloe fired back and flat out told him, "I don't like this new version of you."

I am personally closer to Chloe; in most situations, Chloe is incredibly controlling and manipulative. Even in this instance I want to call her out on it, but I know if I do, she will immediately play the victim, twist my words, and make me feel like a horrible person.

After Chloe sent me screenshots of their argument to prove her point, I privately messaged Mason to check in and see if he was doing okay. Mason coldly responded, "We aren't friends anymore," referring to Chloe.

Meanwhile, Chloe sent me an incredibly long, sad monologue about how bad her life is right now. She is clearly hurting. I gently suggested she talk to a therapist, and she admitted she has been in a really dark place lately.

I am anxious. I'm worried people are going to start threatening to leave the group, and I'm scared that when our regular group schedule starts back up, the whole dynamic will be ruined.