My nephew began experimenting at 14, became a daily user around 17 and died of lung cancer at 38.
Sad all the way around, as he had a full engineering scholarship but dropped out as his general education classes were boring and too much of a drag and a big waste of his time!
He ultimately worked in restaurants but couldnt be trusted as a waiter either to keep his orders straight or always to remember to return the cash to the register.
No offense, but your nephew sounds like a flake.
Anyone who uses any drug to the point it affects their life goals...will use any drug to affect their life’s goals.
And there’s dozens of them to do the job.