Depends on how much money you want to spend and what games he wants to play.
There is also another option in the form of cloud gaming via GeForce Now, this allows you to play some games you own via PC games stores like Steam or Epic. Any current basic PC should do, though it is recommended to use a wired ethernet connection than wireless as your streaming the game from remote server (this cuts down on latency).
Even if you stop using it you still own the games and can install/play them when you get better PC hardware.