I know that many of us have been through Post Traumatic Stress, I did and I had night terrors for over a year, waking up screaming and becoming an insomniac because I was afraid to go to sleep.
If it can have that damaging an impact on we adults, I cannot imagine what it can do to a child. I think that with healing guidance from a caring parent, they can get past it, therapy helps too. But I think it is something that takes years of healing to overcome, whether it's just bad memories or Post Traumatic Stress.
Addiction truly is a family disease and each member needs to find their own healing and peace. I think this is one of the most important things, you cannot stuff the emotions that come with living with active addiction. The only way through the pain is exactly that, we have to walk through it to get to a better place.
Hugs and prayers to all who suffer, the addict and their families too.