“I have a four year old autistic son, almost a year ago my soon-to-be ex-husband left town and I do not know where he is. I am trying to find out how to take his parental rights away when I don’t even know where he is. He has not paid me money to help, or contacted me.”
You can’t take his parental rights away, nor should you even be thinking of it. It is petty, angry, and selfish of you to even attempt it. He is still your son’s father, and your son deserves the opportunity to know who is father is, regardless of what sort of father he ends up being. It is your ex’s choice to be whatever father he chooses to be, not your choice to un-father him, and leave your son fatherless.
The issue of his not paying support is a separate issue, and *that* is an issue you can, and should, peruse. So, instead of “trying to find out how to take his parental rights away”, try to find out how to find him.