When you are a parent, seeing your child become an addict is one of the most trying times. Here is your child, someone you cared for their whole life, someone you loved unconditionally, someone who you would do anything for, someone you took care of when they were sick. Now here you are, watching them dance with the devil of addiction. It's not what you want for your child, something that that will shake the core of any parent, something so impossible to understand.
You begin to question everything. You ask yourself, what made them an addict? If you find yourself blaming yourself, don't, it is not your fault. We all make mistakes as parents, good parents are not perfect parents. All of us could do better, in some way. But once a child is grown, they can not blame you for making the decisions they are making today. They have choices. Building up/ tearing down, Addiction / detox, Fighting / loving, Honesty / deceit, sobriety / stupidity, Working / slacking.
Love the addict not the addiction. The addict was your child long before they were an addict.