If youre wanting to get them an air powered tool, id say a sanding DA, or a small 3 inch hand grinder so when theyre cleaning metal up, they can get it clean clean. Other than that a blasting cabinet is essential for a restoration. Other than basic hand tools to complete a restoration, what i use most is body hammers and dolly's. Ive found a cheap body hammer can be used on many things other than beating sheet metal. Theyre great when you dont want to swing the 3 pound sledge at something.