Hans, I feel your pain and went through something very similar with my wifes youngest son.(second marriage)
The pain and anguish she went through as well as the lies and emotional blackmail of an addict took its toll on her.
I think the greatest shock to her was that she learned she was actually the enabler.
Logic as you say never worked and it cost us a whack of moolah to get him through rehab.He is now clean for 3 years.
Glad to hear your daughter has been clean for 17 months as I understand it heroine is the hardest drug to beat.
Kudos to you for offering your support as it was through the help of a strong support group that we got through this.
I too had some good support from one or two guys here and a certain oom in PTA who gave a lot more than he knew
Oh and good news that you have bought yourself a sound system..looking forward to seeing it in the members kit pictures thread