My son and some of his friends had 'hidden' in the tunnel area in the Al Bida Park area during ramadan a few years ago. A qatari man saw them, and found them sharing a can of coca cola, so he called the police. Fortunately another resident here showed up and intervened, stopping the police from taking them all off to the police station.

They were made to apologize, even though they'd taken the precaution of 'hiding'.. in the tunnel, and gathering in a closed group so that no-one could see what they were doing... the Qatari man still called the police. He actually had to follow them into the tunnel (not the normal course of pathway for him) to find out what they were doing.

So I think our friend would do well to drink in public and see what the consequences will be. We are informed that eating and drinking is expressly not allowed, and even certain exceptions are expected to use discretion, so why push the limits.
Angel