McCready has been involved in a messy custody battle over the boy with Inge and her ex. Zander lived in Cape Coral, Fla., with his grandmother, who has legal custody of him. He is allowed to stay with his father on occasion, but can only see McCready on supervised visits.
"Zander is used to being in Florida with me and her mother. I'm worried about him being moved around," McKnight told HLN Thursday.
In a statement Wednesday, McCready's spokeswoman told ABC News that the singer is keeping the boy out of concern for his safety.
"Since at least January 2011, Ms. McCready has been desperately advising the court, and others involved in the Ft. Myers, Florida proceedings, that Zander is in danger, both physically and emotionally, at Inge's home. As a direct result of being a mother (not an actress, not a singer), Ms. McCready took action to ensure her son's safety," the singer's spokeswoman Kat Atwood said.
Inge has denied the abuse allegations.
At some point during a visit on Tuesday, McCready took Zander and fled to Nashville.
Seals ordered McCready to return to Lee County, Fla., by 5 p.m. Thursday, but the singer made it clear that she had no intention of doing that.