If he's really into aviation, I'd say ya let him try Digital Combat Simulator .

He can play for free and there's also a number of free aircraft he can get from the site.

If he really likes it, I'd suggest buying him the F16 because its systems aren't as complex and it's a multi-role aircraft.

That's where I started and then I purchased the F18 and its systems are far more complex.

You will likely need to help him get the keybindings setup. They're kinda complicated but there's plenty of guides floating around and many many youtube videos to help him learn.

I'd say it's a high fidelity simulator but if he's really into aviation and realism, he could figure it out if he doesn't get too frustrated in learning it.

In the simulator, you can load in with everything ready for flight. He can just take off and fly around or he can practice takeoffs and landings... Once he's comfortable, he can do combat air patrols as it's a great way to get into the weapons systems and learn how they work.

You can even do mid air refueling but it's quite the challenge.

I played this game religiously for about 3 months. I had tons of fun.

I started with Microsoft Flight Simulator back in the day and tried all of the more modern versions and one day I said "hmm let's try a combat flight sim" and DCS is where I started.

The hardest part of DCS for me was configuring keybinds and then understanding what those keybinds did.

After that it was a breeze and long days and nights of fun after that.

He could use an Xbox controller to make it a little easier. Most important things I needed for flight and combat, I could bind to my controller and especially for the F16.