Pedal effort can be reduced by sizing different bores on the master and slave, but it's a tradeoff. Reducing the pedal effort also increases the stroke, no free lunch when you're doing a certain job requiring X amount of lbs to move, requires Y amount of energy.
It just gets there by either a long stroke with less effort, or a short stroke with more effort. The same amount of energy is required either way. It's just simple physics.
The assisted power from say a power steering pump, or as I first posted an electric pump. There is also a way to pulse an electric over hydraulic valve electronically causing a dwell reading, or so much time open that can slow down, or speed up a hydraulic action.
It can be done, but depending upon how much time and money the customer, and you is willing to expend. I guess it boils down to how much assist he's going to need with his condition. The equipment needed is going to vary upon how much physical effort he can put into each clutch disengagement/engagement continually. Stop and go could be a nightmare in this situation, and require much more assist than just a leisurely drive in the country.
One other thing is if he float shifts after getting the car moving he's going to do a lot less clutching. Having driven big trucks for a few years, it takes some getting used to, to float shift, but of the 2 trucks I own with manual transmissions, I only use the clutch to start and stop, if he gets fairly proficient at float shifting you can kick the vehicle into neutral when stopping saving some more clutch effort.
The electric hydraulic pump used in outboard boats to raise and lower the engine/drive unit would be plenty to run a hydraulic clutch.
