Student or Learner
"I would like you to imagine that there is a person who used to be a junkie. He went to a rehabilitation centre and stayed there until he became an unaddict but he thinks that he might start taking drugs again if he gets a chance.
Can we say "He can fall for it again" Or "He can relapse?"
There is a drug seller who wants him to start taking drugs again so that he can earn money from him and pursuades him to start taking it again.
Can we say "He (Person who was an addict) can fall for the prey?"
Remember - if you don't use correct capitalisation, punctuation and spacing, anything you write will be incorrect.
I would perhaps say:
He gave in to his desire for the drugs he craved.
It sounds like he's still an addict. Former addicts (to drugs, smoking, alcohol, chocolate, coffee, etc.) don't lose their addiction merely by abstaining. They lose their addiction when they lose their craving and their abnormal substance seeking behaviour.
"He might fall prey to drug addiction." Is it correct?
The sentence is OK.