William Gomez, the missing Carrollton, Texas, man last seen Sunday driving off with his grandchildren, has been spotted in Indiana and Kentucky as authorities continue their search for him and Marcus and Dominique Gomez.

Gomez’s family believes his issues with memory loss may be to blame for the eerie disappearance. His condition is also worrying authorities who are trying to locate Gomez and his white Jeep Cherokee, also believed to be carrying 8-year-old Dominique and 7-year-old Marcus.

"Mr. Gomez has a medical illness that causes memory loss, so we're very concerned for him and also for the children," Carrollton police spokeswoman Nicole Rodriguez told NBC DFW.

Authorities are tracking the use of Gomez’s credit card to help locate him. The 57-year-old used his card Monday at gas stations in Arkansas and Tennessee, according to the Dallas Morning News, and on Monday night, the card was used again to purchase underwear for his grandchildren at a Sears in Paducah, Ky.

About $21 worth of merchandise was purchased on the card at the Sears store, and Gomez reportedly asked a store clerk for directions back to Dallas, according to KLTV.

By Tuesday morning, it appeared Gomez, Marcus and Dominique were in Indiana.

“Recent debit card activity shows that Mr. Gomez has turned north and is located in the northwest corner of Indiana,” Rodriguez told the Morning News. “We have notified the Illinois and Indiana State Patrol and sheriff’s departments. We have also sent a bulletin to the National Center for Missing Children. We are currently in the process of calling agencies north of Mr. Gomez’s last location.”

Gomez’s wife, Maria Gomez, told WFAA that she’s been on edge since the disappearance of her husband and grandchildren.

“They must be scared,” she said of Marcus and Dominique. “They’re not home.”

Maria Gomez said her husband is in a fragile mental state.

"I think he is confused; he thinks he's driving home," she told WFAA. "He was raised in New Jersey, so he could be driving home... but we don't know."