SoCopasetic,
I'm thinking back to my days in high school, and at that time my school was pioneering a program called peer support, which was groups of high school peers available for discussion groups, mediated by a trained counselor.
I'm assuming your daughter's school counselor is aware of the young man's death, but is the counselor also aware of the specific type of relationship that your daughter had with this young man, and also that he was an addict? With this information, perhaps the counselor could help facilitate the coming months in school with your daughter, working with teachers, etc., to give her allowances due to her grief, etc. Or perhaps the counselor could help select a suitable group of peers where your daughter could have a mediated discussion with other of her grieving peers.
At any rate, some professional third party grief assistance would be very helpful to your daughter, especially in this meaningful last year of high school with graduation and prom and other landmarks she will have to navigate.
Perhaps somebody here can post with their experience in such matters. I have worked in hospice and with grieving adults, but not with adolescents. But I can say that having assistance via a professional can give her a structure to work through her grief, learn to talk about it and process it, and make much more progress in her grieving process than just trying to muddle through it the best she can without such knowledgeable assistance.
There are probably local grief hotlines you could call to get other ideas and references, as well.
And of course, there is always your local Nar-Anon group, which is a support group of friends and family of substance abusers. Many of them, unfortunately, will have experience with knowing an addict who died. Nar-Anon is free and open to the public. If there are no Nar-Anon groups local to you, then you are welcome to try Al-Anon, the sister type group for friends and families of alcoholics. The principles and issues are much the same between groups; it's just the substance in question is slightly different. You would be welcome at either, and some communities even have Al-ateen, which is Al-anon for teens. Google any of these terms and you will find their websites that will direct you to a local meeting finder or phone hotline for assistance.
As our F&F moms come along and post, they will have insights, too.
CLMI