Left leg and left hand? In that case, hand controls are silly (they rely on you steering with left hand), just needs a normal auto with a steering ball to use one hand. Bear in mind that it should have power steering for him to be able to use it safely.
Motability sucks for people with convictions doesn't it, five years my missus brother has to wait before he gets back on the scheme (but it has taught him not to drink and drive )

Depending on how good his left hand is, as he can accelerate and brake with his right foot, he could have the clutch control on the steering wheel provided he can change gear with his left hand.