I would reach out to Charachorder and ask if you can get a priority shipment of one of their products. They spend a lot of time making informative videos about their product, and disabilities is a significant use case. If your friend is willing to make the tradeoff of a steep learning curve for raw input speed, this seems like your best bet. I have never personally used the device, but from what I can see, it requires very little finger movement.

https://www.charachorder.com/