Well, here is what I think. Build a wheelchair with hydraulic lifts that actually tilt him back about 15 degrees and secure the wheelchair in 5 points for safety So the idea is he wheels up to a spot and the lifts start to get to work. You'll want to use a camera and write some software which will do facial and voice recognition. He will speak "GAME START". Then use a motorized actuator arm that drops down a screen hidden in the ceiling drywall joists. Did I not mention the actuator arm yet? No, ok, well you need an arm cut into the ceiling to fit inside the joists, now this only works if the joists are 16" center joists, but you need a servo motor which detects when the hydraulics from the wheelchair are enabled. Once it detects the hydraulic lifts the actuator arm automatically deploys and drops down a monitor at the correct height and angle. To avoid the whole system overheating, I recommend a liquid nitrogen cooling system. Don't get one of the cheap chinese knockoffs either. Get a genuine Komatoko model to cool down both the servo monitor and hyrdaulics. Next you have to consider the controls. You could have them also attached to the actuator arm for the monitor but what fun is that? So, we really need to think of a good way to mount the controls.
OR.... you could move the bartop to the edge of the table.