Changing a Child's Name: Grandparents Changing Child's Name

Recently, my ex-husband passed away. He had a son who was in the custody of the child's maternal grandparents. Since his passing, the grandparents have received consent from the child's mother to change his last name to theirs.

The issue: Over the years many people had always questioned if my ex was the true biological father. He even questioned it, but was afraid to have paternal testing for fear of losing the son he had been raising. Now in his passing, how do I bring up the issue to the court that there may possibly be another father and that the mother may not be the only who has to give consent.

I feel that after all this child has been through and the lies he's been fed over the years, he has the right to know the truth. The child just turned 10 years old.