If your Wii has GameCube ports, I'd opt for official GameCube controller. Otherwise, I'd probably go with official Wii U Pro Controller as it's possible to pair it with the console through
Nintendont.
Controllers with digital triggers work with GameCube games.. even if they'd make use of analog triggers? The problem I see would be that it'd go from 0 to 100 since it can't be controlled.
I read Wii Classic Controllers work with GCN games via
Nintendont and it'd be semi-wireless so that could work for him.
Edit: Official GCN controllers in good to very good condition aren't cheap, maybe in Italy they are. I bought a third party GCN controller from the brand "Under Control" it looks pretty much identical to the Retro Fighters N64 controller, although I've yet to test it.
I did notice that the B button was placed a bit inconvenient since the camera stick sorta goes too near to it.
Retro Fighters N64
Under Control GCN
It feels pretty good, no loose analog sticks, and a quality third party controller (most third party controllers are junk, except Hori).
Honestly I'd be happier if I could buy a non-genuine wired (USB) PS3 controller. it is more ergonomic and usable on pc. Do you know if non original PS3 controllers still work? I'd like this here:
There are good and bad fake DualShock 3 controllers, but you're better off buying an official DS3 controller if you really want as they're built to last while fake ones may eventually quit on you.