Much progress has been made with the power in Lumens; but there are temperature problems; how long does your son want to keep it on at maximum brightness? Seconds? Minutes? More than three minutes? More than 10 minutes? Or do you aim for pure distance, i.e. seeing a bright spot at 2km? All these questions could be summarized in one: What does he need the flashlight for?
What can’t he give up and for what is he willing to compromise?
If size matters, and you still have time (6 months? ), you could wait for the BLF version of the Sofirn SP70: over 6000 lumen and likely 250 kcd. The current version is good but the BLF version will be better. Price under $60
I’d second this if he wants something small.
If he doesn’t mind something a little bigger I’d go for the Convoy L2 or L6. Best bang for the buck in my opinion.
He got the Sofirn C8T for 17 usd in the Aliexpres official store . The batteries are the most expensive thing , the good enough ones cost at least 26 usd.
Too many nice things out there , the current emitters are very tempting . Currently I´m tinkering , a lot , with old stuff bought prior 2015 , xlm , osram oslon , some nichia .