Tics can begin as early as age 2, but are most common in middle childhood, ages 8 -12. They are very common, and can affect from 5 to 10 % of children. They are about three times more common in boys than in girls.
The cause of tics is not really understood. Rarely, they can be a sign of a neurological disorder. They tend to run in families, and it is well known that certain medications can produce tics. Psychological factors are also felt to play a role.
Most tics will last for a short while and then go away, and generally no treatment is required. There are some children who have more significant and prolonged tics (greater than 1 year), and these children may have what is called Tourette syndrome, a disorder in which the tics are severe, frequent and can interfere with daily activities. Tourette syndrome is a lifelong disorder, though it often improves in adolescence or adulthood. There are medications that are available to manage severe tic disorders, and a number of behavioral treatments can produce significant improvement.
Thus I think it is important to have your grandson see his pediatrician, first to sort out whether the behaviors you mentioned are truly tics, and next to determine a plan for managing them if they are tics.