My fiance has tourette's.
t is hereditary, but skips a generation, so look to your son's grandparents. It doesnt always present the same. for women it is more like OCD. Plus in mild cases it disappears, so his grandparents may seem just fine now, but perhaps as a child?
Also, try not to focus on "fixing" him. The tics will gradually subside and likely be gone by his early twenties. My fiance now only has some mild verbal tics, usually only when he eats. It is more adorable than annoying or disruptive. What I would suggest is just be super supportive and nurturing. People with Tourette's often suffer from anxiety or depression or paranoia. These silent symptoms can easily go unnoticed by parents, but do the real damage. My fiance still has lingering anxiety. And he spent many years alone with few friends and no girlfriends. When I met him he was still silent, but boy did I wear him down. He is now quite a happy fellow. But as for the tics, I wouldnt medicate your son unless they were really bothersome or offensive.