I would personally never buy this(with the red dot), I posted that just for comic relief. I have used and will continue to use the ones with back up iron sights. I can easily aim at targets under 50 yards with both eyes open using an ACOG. The only firearm I would consider using a red dot on would be a shotgun.
I'll reiterate this again, your choice of optics is directly relevant to your philosophy of use, training, personal preference and budget. If I were to identify, engage and neutralize targets in an open combat situation, I'd pick ACOG all day. Unless I were given a red got and a magnifier. Which would mean maintaining 2 pieces of optics, which might seem like no big deal at the local range but it is a big factor otherwise. If I was to do room sweeps then I'd just go with a shotgun. All that being said, is ACOG perfect? no. Is for him? I don't know. Should he go with a red dot? Probably yes.