He has a little bit below the elbow; enough for a prosthetic at the very least
Looked into joysticks as well; it seems that the Xbox has made steps for one handed gamers more than Sony has
you know in a screwy way that kind of makes sense, because xbox is a division of Microsoft, and Microsoft started out as a pc (software) company.
on the other hand, I think Sony has been working on the other end, by working on better prosthetics/robotics.
I realize that may not directly help your brother but just tossing it out there.