I have an eight year old with OCD,I think each case is different.Have different obsessions,you think he has got over one of his obsession not long before new one appears. I know if you feed into obsession it gets worse.Its really hard seeing him upset.Does your son have any other problem?My son has been blinking a lot and head makes jerky movements,took him to specialist they said they think its tourrettes.Just feel so helpless.
Take Care