I also have a 12 year old son that is very iinterested in fire. He is genuinely curious about it, and has also watched YouTube videos related to these “experiments”. One thing that has helped is providing him with the tools to do his own science experiments, supervised of course. We subscribed to a monthly chemistry box that sends everything needed to complete a few experiments. Its educational and fun. Maybe your son is just really curious as well and this may be a good avenue to let him experiment and have bonding time with parents. Good luck!