pending greencard for years???

[oxossi]

hi, a friend of mine is having problems, he got his conditional residence through marriage years ago, then after two years he applied for a permanent, he sent almost no documentation proving that the marriage was real and that they were still married. Apparently a friend helped him do the paperwork and didn't tell him to mail the paper tray with pics and other documents.
So two years have passed and he has no green card, they have stamped his passport and he has been able to leave the country and come back.
He is still legally married but him and his wife don't live together, the UCSIC called him for an interview and asked him for more documentation prooving that the marriage is still good, he showed up with some but that wasn't enough so they gave him another chance to send more.
I think he should have said that the reason that he doesn't have more documentation is that they have separated but still he didn't.
In case it is denied, what are his options since he's been married for 5 years although the permanent i-751 hasn't been approved.