He mentioned South Carolina, so it would appear he wants to know if his friend has sufficient evidence to establish adultery so as to pursue a fault-based divorce under that state's laws.
Apparently the evidence is that after the friend allegedly beat his wife, causing her to file a police report and move out, she has moved in with a friend who is male and has gone on trips with him. It's not outside the realm of possibility that the living arrangements and photographs would be sufficient to establish adultery, as in South Carolina you don't have to establish any actual sex acts to establish adultery, but it's something he needs to discuss with his lawyer.
If a divorce has been filed by the wife, I would assume she's alleging physical cruelty.

