It just seems bit overwhelming to him. And I think he likes being chauffeured around!
Just a little psychology here.. is it the other way around? likes being chauffeured.. due to being overwhelmed by the thought of driving!
I would suggest if this is the case some root cause analysis may be the "motivation" required.. what is the core reason for being overwhelmed? past trauma or bad experience, lack of self confidence, maybe just the size of vehicles.
My reasoning behind this stems from my wife, she is a good driver however dislikes interstate driving and prefers I do it (ie.. being chauffeured). Her "dislike" stems from a fear of semi truck size and the potential for another driver changing lanes running into the side of her. As I explored this with her the true root cause came down to interstate speed, interstate travel scares her because everything is happening "really fast" (and the size of semi trucks). Once the point of everyone traveling in the same direction at relatively the same speed is safer than surface street travel due to everyone going in multiple directions at different/constantly changing speeds (which oddly enough she was comfortable with) she became more comfortable in interstate travel, then I put her in a semi truck ( was my job) and her perspective was changed.. it hadn't dawned on her the visibility that commercial vehicles have, she believed they had the same distance perspective of a car driver. With experience and some coaching her fear has subsided some and she has become more comfortable with interstate travel, still prefers rural interstate over city but more comfortable none the less.