NMC ds has pretty much no fine motor skills but can lift his arms (eventually) to let you put the tray on his chair or to "wave" or "high 5"
They are looking at designing a control system that will be easier to use than the conventional joystick as theres no way he could ever use one of them, maybe something bar related as he can grip a bar after a fashion but would probably need those glovey hand grips to help him, like they use on trikes?
Talking about trikes we are going to be getting one of those Tomcat Tiger trikes, Bobs going to adapt it so that i can use ds own headrest with the band round it to support his head, likewise with the powerchair, just much easier using something i know work rather than making do with what they come up with!
www.tomcatspecialneeds.co.uk/products-tomcat-tiger.htm
www.dragonmobility.com/