As the court-ordered deadline looms for an Idaho mother to physically present her two missing children to authorities, a family member is losing hope that she will do so.

Lori Vallow, 46, has until early Thursday evening to bring her 7-year-old son Joshua “JJ” Vallow and 17-year-old daughter Tylee Ryan, who have not been seen since September, to either the Idaho Department of Health and Welfare or the Rexburg Police Department, according to police. If she does not do so, Vallow may be subject to civil or criminal contempt of court.

Larry Woodcock, the biological grandfather of JJ, told ABC News’ Amy Robach on Thursday that he does not think she will bring forth the children.

“Do I believe? Yes, I want to believe that [she will],” Woodcock said. “Do I think that she’s going to bring them? Honestly, no.”

“Nothing with Lori right now makes sense,” Woodcock added, noting that the Vallow he knew for the last 12 years “is not the same person that is here on Earth today.”

Vallow, who lived in Rexburg, Idaho, up until November 2019, was found over the weekend in Princeville, Hawaii, on the island of Kauai, with her new husband, Chad Daybell. The two were still in Princeville as of Wednesday afternoon local time.

They were served with a search warrant Sunday for a vehicle they were in when officers with the Kauai Police Department pulled them over.

The police statement does not say that Daybell would be held in contempt of court. A lawyer for the couple didn’t respond to ABC News for comment.

The children were not with Vallow or Daybell, and police said there’s no evidence they ever were in Hawaii. Authorities have said they think the children’s “lives are in danger.”

Assistant Police Chief Gary Hagen told ABC News that he could not detail exactly what penalties Vallow would face if she’s held in contempt of court, citing the child protection act.

The Madison County prosecutor in Rexburg similarly said in a statement that child protection cases are “sealed and confidential.”

“While the Court did allow us to announce the existence of the case and the order that Lori Vallow produce her children, any and all other documents, hearings, and court filings are sealed and confidential by law,” according to the statement.

The bewildering case made national headlines in December, after police announced the children’s disappearance.

Yet concerns for the safety of JJ and Tylee arose well before.

Lori Vallow’s former husband, Charles Vallow, who is the adopted father and biological granduncle of JJ, filed for divorce from Lori Vallow in February 2019, court records from Maricopa County Superior Court in Arizona show.

He expressed a “genuine fear for his life” and wanted to ensure that JJ was safe and cared for, according to a statement from his attorney Steven Ellsworth that was sent to ABC News.

In July 2019, Charles Vallow was shot and killed by Lori Vallow’s brother, Alex Cox, in a case police are looking at as self-defense after an altercation occurred between the two inside Lori Vallow’s then-Chandler, Arizona, home.

Cox was then found unresponsive in his Gilbert, Arizona, home in December 2019. He was later pronounced dead, and a spokesperson for Gilbert police previously told ABC News the department still was waiting for autopsy results to determine the cause.

In between Vallow and Cox’s death, Chad Daybell’s wife also died under circumstances now believed to be suspicious, authorities said.

The remains of Tamara “Tammy” Daybell’s, who died on Oct. 19, 2019, were exhumed in late December, police said. Authorities are looking into whether or not she was poisoned.

In November 2019, extended family requested a welfare check for JJ at Vallow and Daybell’s Rexburg home.

Vallow falsely told police the children were staying with a relative in Arizona, and the next day when police returned to the home with a warrant, both Vallow and Daybell had “abruptly” left the city.

Rexburg police have lambasted Vallow, saying she “has completely refused” to help in the investigation and instead chose “to leave the state with her new husband.”

Rumors that Vallow and Daybell are part of a cult have also stirred since the children’s disappearance.

The rumors appeared to stem from their involvement in Preparing a People, an organization that preaches about preparing citizens “of this Earth for the second coming of Jesus Christ.”

Preparing a People issued a stark and lengthy denial.

“It is not a ‘group’ and is not a ‘Cult’ or something people join, but has educational lecture events that can be attended or watched on video,” their statement reads. “We also do not share any of Chad Daybell’s or Lori Vallow’s beliefs if they are contrary to Christian principles of honesty, integrity and truth.”

Woodcock told ABC News that while he has ideas about why Vallow isn’t helping authorities, he does not have a truthful answer. He thinks that she changed after becoming involved in the so-called cult.

“Ever since she’s been involved in this doomsday cult, that is not the same Lori that we knew for 13 years,” Woodcock said. “And the last year has just been not understandable. We just don’t understand how any mother can walk away from her children for months now …, so I don’t know who that person is anymore.”

ABC News’ Mike Repplier and MaryEllen Resendez contributed to this report.