I would recommend he swap to an auto. Don't make it sound like he is incompetent just explain that automatics have their clutch plates immersed in oil so they don't wear out. He might buy it as it is true.
My father drives an auto so the clutch & gearbox is safe. His only problem is he drives into things. I often wonder with all the repairs, fuel & registration fees would it be cheaper for him to use taxis.