My nephew needs to file for custody

I need to know which forms I need to help him fill out to file for custody of his three year old son, the mother is mentally ill and has recently decided to no longer take her meds causing her to be a danger to herself, my nephew and her son. She has also begun making up lies and what I would almost consider alternate realities in her own head. She is saying she is going to file for custody in the morning and we need to be a step ahead of her for the sake of my great nephew, if someone could help me that would be wonderful thank you.

Rosebud
ladyrosebud83@yahoo.com

If the mother was unwed when she had the child, she, by default law, has sole legal custody of the child. There is no need to for to file for custody. She already has it.

The only way you would stand any chance of winning custody is if you can adequately prove she's actually harmed the child. Judges rarely take custody away from mothers, and there has to be pretty compelling evidence to prove it's for the best that she not have custody.