He needs stop alcohol for a start.. alcohol is the main trigger to get coke. He needs delete all his coke dealers out of his phone, and mates and fam who have it. Avoid pubs at all cost. Its in every pub going.
Come off social media aswell, and basically avoid anything to do with coke. If hes picked coke up on say asda carpark… he needs avoid going even there as it triggers his brain to get coke.