Do biological grandparents have any rights after their son signed his rights off? The grandmother treats the children differently and I can't take it any longer. She has threatened to take me to court because she says she still have rights because she has been in the 5 yr olds life since day 1. Is this true?

First, any question on law needs to include your general local as laws vary by area.

However, an adoption generally severs any rights of the biological family. On the other hand, states are recognizing grandparents rights more and more. If the grandmother can prove a bonding that benefits the child, she might get some rights.

What is your relationship to the son and why would you still have allowed the bio family access?