I'm so sorry your family is going through this. You have to get him in a rehab program immediately. There are organizations that will help with the costs if you need it. Contact local organizations in your community and talk to them about the different types of treatment. He needs to get over the drug addiction before it gets worse.
He is obviously grieving over the loss of his friend. It always hurts that much more when it is a suicide. People all wonder why, feel guilty even though it isn't their fault, etc. See if you can get him talking to a therapist about his friend's death. Even if he doesn't want to talk about it, they may be able to suggest other ways for him to let his emotions out. He can learn healthier ways to deal with the grief than self-medicating with drugs.
Here are some hotline phone numbers that I hope will help you.
National Youth Crisis Hotline 1-800-488-4663
National Institute on Drug and Alcohol Abuse 1-888-644-6432
Marijuana Anonymous 1-800-766-6779
National Drug Abuse Hotline 1-800-662-HELP
Mental Health Info Source 1-800-447-4474
Help Finding A Therapist Hotline 1-800-THERAPIST
Adolescent Crisis Intervention and Counseling Hotline 1-800-999-9999
Be Sober Hotline 1-800-BESOBER
Here is a website that I thought had some good information:
Troubled Teens Resources
Continue talking to Social Serices. They can be a good source of information and might be able to help you get him into a rehab program.
Good luck and hang in there! Someday he will thank you for it!