contact child protective services in you county.
In most states, the 'danger' would need to be established by appropriate authorities. Until then, the aunt would be seen- by the authorities, as well as the parents- as 'sticking her nose in where it didn't belong'. Contact local law enforcement or DSS. In cases where a minor is in a clearly dangerous family situation, they will move quickly. Having a relative express a desire to care for the child, rather than placing him in a foster home usually plays well in court, since the state isn't burdened with supporting him.
With the aide of a lawyer and the courts.
The godparents might.
You're a Great Aunt to your nephew's son, who is your great nephew.
a nephew's kid to his aunt's kids would be their cousin.
You are your nephew's uncle, or aunt, and his son's great uncle, or great aunt. Your nephew's son is your great nephew.
Your niece's son is your great nephew. You are his great aunt or great uncle.
Your nephew's child is your great nephew (if a boy) or great niece (if a girl). You are his or her great aunt.
You are a great great Aunt (or Uncle) to the grandson of your Nephew.
Your brother's (or your sister's) son is your nephew and you are his aunt if you are a female or his uncle if you are a male.
Aunt.
To your uncle, you are his niece or nephew.
You would be his great aunt. To you he would be your great nephew.