My son also exhibits these tics...particularly the Smelling ( has done this for almost 2 years), he also neck rolls, so bad that his neck is chaffed and raw. He has been presenting tics for almost 1 1/2 now, and was just diagnosed wtih tourettes. Not saying your son has this, but I do notice my son gets anxious, then his tics worsen, then he gets more anxious due to his tics. It is a vicious cylce. My son went through the ringer at the behavorial center at the local childrens hospital to get a proper diagnosis. I would suggest talking wtih your pediatrician. His doctor always told me that if it is affecting his everday life, that is when it becomes a problem. Good luck!
Would you mean his Dad also has the same behavior as if so I would say your son is copying, many habits are learned from family..Not listening is very common and in my opinion a normal behavior in children...and adults ..It doesnt sound like a seizure ,just a habit, maybe ignore the habit do not focus in on it, focus on his positive side ...good luck