Certainly does not look well. A fairly hardy coral so your friend needs to do a run down on water chemistry including Ca/Mag/Alk, at least Ca and Alk.
Also looks like a newer tank so he/she should look at ammonia and nitrates as well.
At this point dipping it would be beneficial so I would trouble shoot chemistry first.
What flow is the piece under and how intense is the lighting?
The commonly available fish, inverts and corals come from vastly different geographical locations so it's not too surprising to see one coral, invert or fish respond or not respond differently than everything else in a system.