If you're using the word "skeet" literally, you're talking about a specific shotgun sport, the one with two launchers and eight shooting positions. If he ends up getting INTO it, the gun he's going to want is not going to be cheap. But here are a couple of things to keep in mind as he selects his first:
1. Skeet is short range. You need very little, or even no choke. Interchangeable chokes are fairly standard, but if he buys a barrel with a fixed choke, it should be cylinder or improved cylinder, nothing tighter.
2. Targets cross in front of you. You have to be able to swing that gun quickly, so shorter barrels and lighter guns are an advantage.
3. Skeet deals with 2 targets simultaneously, so being able to take a quick second shot is essential. Either a semi or an over-under is fine. Pumps are a handicap.
He needs to find a gun that meets these criteria and fits him well. Honestly, recommending a specific model isn't necessary; if it fits him well, and it functions reliably, he'll be fine.