Bobh... Thanks for your response. I am stumped. With the exception of those 7 days of reintroducing gluten in mid-February, he's been GF since Jan. 1. He is still ticking and experiencing OCD (not anywhere near the level of June-November, but it is definitely there and effecting him).
He did two rounds of antibiotics in the fall, with the last ending in mid-November. He seemed to start to improve in the last week of December, though not to 100 percent. His gluten elimination diet started the first day of January. Everything was gone by mid-January ... new tics, old tics, anxiety, concentration issues, near constant hopping, fear of certain foods, but most importantly he acted like himself and smiled and felt good for the first time since this all started in June.
Maybe the timing of the elimination diet just went perfectly with a fall of strep antibodies (due to antibiotics) and he was just going to get that good, regardless of his diet. But It seems very coincidental that it all came back when we reintroduced gluten. I did take him for a strep test to rule it out. When he went, he had a low-grade fever and a red throat so was fighting something, but the strep test (rapid and culture) was negative. Maybe a combo of gluten and a cold (or just a cold) made him flare. Maybe he is moving from a transient ticker to tourettes and this is just going to be how he waxes and wanes.
You and your sister have a point about medicine (and treatment in general). What works once doesn't always work again.