Concerned for my friend I care about, as friends isolated them, who can I trust as I’m torn between the them, and nobody cares ?

Few weeks ago, our friend group had a big bust up and isolated a friend I love and care about, over reasons I felt was pety, and also cuz he fell out with his best friend, which should of been a private matter and took her side the situation esculated so quickly and they keep building up lame excuses I could of disproved.

as they wanted to leave him,I never agreed and they dragged me into the mess but they never listened to a word I said and made it into a mess,

furthermore they kept me out of the conversation cuz of “my mental health” and shoehorn it when I had a right cuz I felt I knew him the best since I get him and he knows I do, and I felt they made a mistake. as a result they failed to tell me what happened and let outsiders know with his “bf” was spreading bs about him.

Worst of it I found they with benefits, she threatened me to be thrown out, whilst going through other personal stuff,(I’m a adult) but also she been saying things that could be determential to his life and turned everyone against him and me basically, only I’m the only one who know all this is a lie, My gut telling me I’m right, as they deleting and hiding sh*t, they think I’m heartbroken by him but it hasn’t been clear to me why, cuz I can see through it, I’m more heartbroken that they gone cold and done this to him. But also I feel they betrayed me in the crossfire, what saddens me they being nice to me in all of this and they yet to know how I feel. But then I feel I need to tell him what’s up.