Pray, and tell her to pray. If she has raised her son with the knowledge of what is right and good, and he still chooses wrong, there is not much she can do. Like I did, this kid will have to learn through experience how not to do the idiotic crap. That's all we can do.
I remember after Elvis Presley's death an interview with a half brother of his. He stated, the drugs Elvis was involved in at the time had complete control of Elvis. He said if God can't get one off of drugs there isn't much hope.
Elvis was raised in church and, knew the ramifications of drug use, but the hold they had on him couldn't be broken.
There is plenty she can do. See message #215.
The pray the entire time for the guts to do it.