Divorce and Green Card

Hello, I'm asking for a friend. My friend has a pending I-485 right now. His wife filed together as a beneficiary and I think they should be hearing results in the next month or so. They're currently going through some trouble in their relationship though, and my friend is seriously considering getting a divorce. How will this affect both of their GCs? Will it be different if they get a divorce after they get green cards? Anyone know?