Hello Claudia,
I'm new here, but also have lost someone I love to drugs and alcohol. I am so very sorry for the loss of your son, and I think your message is very beautiful and very true. It's so easy to forget to say those words, especially when everything is in chaos and confusion as it usually is where drugs and alcohol are involved.
I lost my ex almost 2 years ago to drugs and alcohol, and still the most painful thought for me is that maybe he didn't know how much I loved him. I am crying writing this.
I wish you strength for the difficult days ahead. Many many hugs xxx