My friends divorce

Rachael
This is probably going to be long so apologies in adavance:
Two of my very good friends are currently going through a divorce but it’s still really recent. They’re the parents to my god children and I have a strong relationship with both of them so I’m working really hard not to take sides, however I think this divorce is best for them both. The hard thing is, my friend wasn’t the best husband and he is looking to me for a lot of emotional support, but I have no idea how to be there for him.
My parents are still together and I’m getting married in 6 months and have never been through a divorce so these are really uncharted waters for me. I have always been the friend who knew exactly what to say and how to make things better but I’m at a total loss because I can’t tell him that she’s right to file for divorce or lie and say I don’t agree with it, but beyond that I just don’t know how to help someone through such a traumatic time. I also live 3 hours away so I can’t be there physically to help him not feel so alone. 
Anyway, I’m really just looking if anyone has advice on how to help someone through this and not say anything hurtful by accident.