Mindy McCready's two boys have been in the foster care system since Feb. 7, and are now wards of the state following the singer's tragic suicide on Sunday.
Zander, 6, is the son of Mindy's ex-boyfriend Billy McKnight, and Zayne, 10 months, is now an orphan. His father David Wilson, Mindy's fiance, killed himself in January.
Mindy's mental and physical health deteriorated quickly after the death of Wilson. Fearing for the safety of the young boys, her father Tim McCready petitioned the court to immediate intervene on his grandson's behalf because his daughter "hadn't bathed in a week ... was screaming about everything and was very verbally abusive to Zander."
The judge granted the petition and the children remain in state foster care. No decision has been made about their future fate.
McKnight will seek custody of his son Zander. He told PEOPLE, "My son needs me. I'm married, working and successful. I'm on the right track and proud of it. I've been sober for years. I just want my son."
Mindy's mother Gayle Inge, who was awarded primary custody of Zander for several extended periods in the past, is seeking custody of both boys and has the full support of the Dept. of Human Services, who officially notified Circuit Judge Lee Harrod that Inge has a "substantial relationship" with the children.
A custody hearing is scheduled for April 5.