1. Their inadmissibility is not really EY's fault, is it? Why didn't you book an EY connecting flight to AMM?
2. By all means go to the Arrivals lounge (if you are allowed into the UAE), but I don't see anything, or anyone here, which suggested that EY allows access to their departure lounges based on a passenger arriving on an EY flight, when leaving AUH on a different airline. What made you think so?