Thank you for your question.
I am Dr. Su S. and I will try my best to help you.
Strobe light can precipitate seizure in those who are predisposed to it.
As he did not have any convulsion, he is unlikely to have any such effect now.
I feel you should not be worried.
Weight loss may not be related to it.
It can occur fluid loss, less intake, increased temperature.
22 gms. can be regained over next weeks.
I hope this information will be helpful.
If you have any query, please feel free to ask.
If you are happy with my answer please click on the Excellent/Good rating.
Wish his healthy life.