I shed a tear the moment I read this. I...as a parent myself, well, I do not think it will ever go away. The only success stories I have ever heard of involved metaphysical and spiritual happenings.
For me, I was suffering horribly from a PTSD for a while, to the point I started to wonder how much of the wrenching experience was psychosomatic. Finally, one night, my diseased grandma (I believe) visited me in a dream, approached me gracefully, then looked at me almost puzzled but really concerned and asked...
"What are you doing to yourself?"
I got her point, and when I woke up the next day, a particularly nasty part of my PTSD experience stopped. She helped me to cease quite literally torturing myself and my body.
May the soul of someone special relieve your heart, because in terms of losing a child, only a spiritual act can allow a parent to let go, and move on. Other than that it must takes years. If I lose my daughter...well...I probably shouldn't type that out.
Bless you and your children, may you live long, happy, contented, peaceful, and prosperous lives x100