We had a similar situation, my son was self harming in school and was hiding under the library table screaming about bad books and meteors. He has Aspergers so his reactions can be extreme but we were very concerned about him. Our other concern was expecting our children to keep a secret in such a high pressure environment as the kingdom hall. I was worried that if they let things slip and we were DF'd as a result they would feel guilty and think it was their fault.
Our fade was to relatively short as a result and very early on we decided that the children should be allowed to participate in activities previously banned such as parties, assemblies, school activities and sports. It took a very short time for them to shake off their conditioning and start building a new life.
We were fading as a family so our choices were based on that different circumstances require different strategies. However one might be that suggesting that until your son is emotionally more stable he has a routine that merans early nights and no late night meetings. The disruption to his sleep routine may be adding to the problem and limiting meeting attendance will start to weaken the hold the doctrines have on him.