HOH is an excellent high end glove, but you can save yourself 150 bucks with the Rawlings Gamer, excellent Glove, nice leather too. I'm sure he plays more than one position which would determine youth size. 11.5 is certainly a good size for infield and pitcher for a 12 year old unless he's a giant, Just don't go real big like a size for outfielder if he plays infield also. You might convince me about spending 300 bucks for a youth bat (not really) but spending that for a youth glove when most mid range gloves are so nice also, it won't make him field better and they are made well and to last.
You can also get the Trapezoid or full weave basket as well in both, which is what you want for a pitcher to hide the grip on the ball. Most major brands make excellent gloves, it's kind of like asking someone for a tire recommendation, everyone has an opinion and they are all (within same class) about the same but everyone talks about them like they are Mario Andretti .
Take him and let him pick out his own glove, after all he has to be comfortable in it. You can steer him to a price range.
In Rawlings,,, HOH is about as good as you get before going up to the Professional Series, Gamers are next and Prospect are the entry level gloves. Each brand has these types of levels in quality of leather. You can find the same thing in Wilson, Mizuno, AllStar, etc.