I've been through this for my mom. A few things come to mind...
1) Don't waste your time on those rubber key keyboards that come as part of the iPad cover - they are painful to use and it will absolutely suck the fun out of writing for him.
2) It needn't be a big keyboard, but an independent keyboard means he can sit the iPad somewhere - on a desk, on the car dash, wherever, and have freedom to put the keyboard where it's most comfortable.
3) Bluetooth is absolutely the best way to achieve wireless freedom with the keyboard - no need for dongles and extra connections.
Mouse on iPad is also handy sometimes, but may not be necessary. That said, this is the best low-cost bang for your buck if you want to test the water without breaking the bank on a bluetooth keyboard. The plus side is it has a track-pad built in so mouse functionality is there for pointing and tapping:
https://www.geewiz.co.za/mobile-key...uchpad-81-keys-for-windows-android-black.html
It's thin, light and well made - very good value for money. If you want full keyboard size then consider one of these:
https://www.geewiz.co.za/desktop-ke...query=microsoft+bluetooth+keyboard&results=20
The difference being that the Mecer has chicklet style keys like a typical laptop while the MS designer keyboard has more chunky full size keys. If I wanted one for being mobile, I'd get the Mecer.
NOTE: I've tested the Mecer on Android, Windows, Raspberry Pi but not iOS. I'll test it on iOS later today and report back.
