The problem with a RMA, as I understand it, is high shipping costs and lengthy delivery times. It would be one thing if he had a spare card to use during the RMA, but without one, his rig will sit idle (or he'll be limited to the Intel IGP).
If I had to take a wild guess about those LEDs, I'd say that each one represents a power phase; the number of LEDs that are on tell you how many phases are in use (and how busy your card is).