Have You Known Someone Who Has Kicked Long Term Perscription Drugs Abuse Without Rehab?

Please help! Good friend is messed up and parents have already sent him to rehab twice. He has no money and wants to get clean. Any suggestions.
I believe he has been taking oxy, percoset, vicadin……..opiates probably 5 to 8 per day for the last year. Was clean for 3 months after rehab last year. Thank you for all your help.
He is 25, works full time and doesn’t want to bother his parents for money . He got on some drug to help with cravings and withdrawl a few months ago. I let him borrow 600.00 to start that treatment but he couldn’t afford the 150.00 per week to keep up. Can he just do it on his own. It sounds easy to do to me. Just stop. But he says it really hurts his body and when the pain gets bad he goes back. Thanks again!