J.S.
Honey... in your last question, you have no need to defend yourself. Take what you need from the advice you were given and leave the rest. Considering what I think is coming down the pike from your mother, please try to develop a thicker skin. What people interpreted from your own words there and read from your situation is how your mother may try to spin things in court, or worse.
That's why my advice consisted of getting a custody lawyer and a child psychologist. The custody lawyer for how to proceed legally, and a child psychologist for how to proceed with your son. And maybe a therapist for how to handle your mother.