Try stroking the skin with a very soft material e.g. a feather then gradually progress to a rougher material and using different textures. I tend to find proximal to distal more stimulating. The idea is to stimulate the sensory system i.e. start the nerves firing with 2 aims - to help reduce parasthesia and to stimulate the underlying muscles depending of your stimulating the flexor extensor surface.

If you can tell us what the motor deficit is and where/what kind of parasthesia he has I could be more specific