Can a quadriplegic driver handle braking-Class A gas/Class C

Sorry, Brian, from a rehabilitation professional's perspective, we'll have to agree to disagree.

To the OP's question, if he is having difficulty operating the gas &/or brake pedals due to his condition, then this is sufficient.

Whether it's an air brake or air over hydraulic brakes doesn't matter; what does matter is if he can operate the pedals with reduced force sufficient to slow / stop the vehicle.