He told his wife Sunday evening that he needed to go to a local Manhattan, Ill., hardware store to make copies of some papers.
"I asked him to wait until morning, but he would not," Annette McGuire said of her husband.
John McGuire was determined to take care of the task on Sunday, even though his wife told him the Ace Hardware store was closed. He left to drive the 3/4 mile to the store at about 6 p.m., but didn't return all night.
"I knew something was wrong when he did not come right home," Annette McGuire told the Daily Herald. When he wasn't home by 10 p.m., she called the police.
"I worry that there are a lot of farm fields between here and New Lenox. He gets more confused at night and could have lost his way," she said.
The 81-year-old man with dementia was found Monday afternoon by his own son in Chicago after being missing all night.
Dementia, which runs in John McGuire's family, causes the man to have little short-term memory while retaining his long-term memory. Alzheimer's disease is the most common type of dementia.
Annette McGuire also was worried because her husband is a borderline diabetic who last took his medication Sunday morning. He also takes medication for high cholesterol, high blood pressure and thyroid problems.
The story, however, took a surprising and fortuitous turn yesterday.
The couple's son, Paul McGuire, was at a wrestling match Monday with his son, Matthew McGuire, a wrestler for Providence Catholic High School. The meet was at Mount Carmel High School in Chicago.
Acting on a hunch, Paul McGuire called his mother to get his dad's old address on Albany Avenue in Chicago.
"Since he was that far, he decided to drive through his dad's old neighborhood," Annette McGuire said. "While he was driving, he called the local precinct and was giving out a description of the car when he saw it coming after him around 2:30 p.m."
Annette McGuire said her son put on his hazard lights and did a U-turn -- and her husband stopped his car.
"When John realized it was his son and grandson, he said he was happy to finally see a familiar face," Annette McGuire said. "They asked him where he slept last night and he said he slept at the cottage. We don¹t know if that was his car or somewhere else."
It had been more than 60 years since John McGuire lived in the neighborhood at Albany and Western, more than 40 miles away from their home in Manhattan.
Paul McGuire told his mother that his father was looked tired and only wanted to find a bathroom.
"I am so happy Paul found him," Annette McGuire said. "They always say the first 24 hours are crucial in these types of cases. St. Anthony was looking out for him."
St. Anthony of Padua is the Catholic patron saint of lost items, the poor and travelers.