Cocaine is a DARI; insofar as I know.
I suggested this to a p-doc before scripting me Ritalin or Methylphenidate.
J3MOd-h3NOW-X3S could be correct here, but I believe after 5 coke sessions and many an hour taking, or trying to take Ritalin; it isn't for some people.
The basics I suggested was you need DA (dopeamine) to reuptake DA. Having taken both these substances; it felt like coming down from 10 cups of coffee with none of the benefits.
Just feels jittery, uncomfortable and unable to sleep. It perhaps bypasses the whole brain barrier, and ends with cortisol; the stress hormone.
Maybe there's a preload that could overcome this pre use, tbh I've tried to no avail.
If your still in the same situation now, benzodiazepines if it's an option. Smoking pot could make it worse for paranoia. Try to just be aware of his situation; and if it gets worse a beta blocker to temper heart rate.
It will wear off, but just keep vigilance.
If he does it sometimes and is okay, it could be something to do with impurities.