I think it was probably these.
I have a pair - They work fairly well, and they're probably as good as it gets for the price. But the lack of "HD rumble" is immediately noticeable on titles that support it, so I always gravitate towards the Pro Controller or the JoyCons. The rumble also feels more crude than even an Xbox 360/One controller, like you're suddenly holding 2 electric toothbrushes.
If he has a Nintendo Switch and he happens to have a Nintendo Switch Online membership, he can immediately hop onto Tetris 99 and compete with other players. Obviously the joycons seem to be a good controller to play Tetris on. I don't know all of them, I use my vivefox joycons which its dpad is actually good for tetris-ing on. Now if he's playing on keyboard which I'm more comfortable on and don't have many left thumb cramps, he should take a look at TETR.IO and Jstris. Those are like Tetris 99, but are for pc. If his pc is graphical enough, do TETR.IO and use the desktop client as it is better than using the web browser. Something basic and still have online functionality, Jstris.
Hi!
I'm using Vivefox Joycons
https://www.amazon.com/Controller-Vivefox-Ergonomic-Replacement-Alternatives/dp/B088K5PF2Y
I charge them with the computer. They come with an USB-C type cable, but no charger, so I just connected it to my computer. Since I work all day and play in the night, they have plenty of time to charge. Today I played about 5 hours straight and they were still charged.
And about BT... I'm not using an adapter. My motherboard has it built-in. It comes with an antenna... and to be honest it's pretty good, I have ZERO lag.