Silvana Bianchi says her grandson's human rights are being violated.
The Brazilian woman arrived in New Jersey last month with hopes of visiting 9-year-old Sean Goldman.
His father, David Goldman, brought him home on Dec. 24 after a five-year international custody dispute. The boy's mother, who has since died, took the child to Brazil in 2004.
Goldman's lawyer says the father is willing to give the boy's maternal grandparents access to the child in time.
A judge last week denied Bianchi's request for immediate visitation.