Motorbike drivers and their passengers are required by law to wear helmets. A survey conducted by the Thailand Accident Research Center in 2009 found that out of the 3,757 motorbike drivers and passengers surveyed, 15% were unaware that passengers must wear helmets and 32% did not wear helmets while riding as passengers. The payment for breaking helmet laws depends on the authorized officer issuing the fine, but is usually between 500-1000 baht.
Quoted from Thailand Law Forum if that helps.
No, it does not "help" but then I didn't need any help as I already know what the helmet laws are.
You seem to be assuming that, in this particular case that I was asking about, the helmet law hadn't been enforced or that the boy wasn't wearing a helmet. Where did you get that information from?