Dennis Day, who was part of Disney's Mickey Mouse Club in the 1950s original, has been missing since July, according to reports.
"He saw it on the news broadcast and called us immediately," Adkins told Dateline. "I called Phoenix Police Department the very next day and we've been working on it ever since. The whole family got in on it."
Day's husband, Ernie Caswell, reported Day as missing. Adkins said police didn't contact her family because "they didn't have any record of family" besides Day's husband, who has dementia and lives in an assisted living facility.
Police said the Phoenix-resident was last seen walking down his driveway in July saying he was leaving a few days to visit friends, reported KOBI-TV.
Day's car also went missing. It was later found along the coast with two people inside who are unfamiliar to Day.
A roommate who lived with Day told authorities he didn't know the whereabouts of Day. Price said the roommate had Day's debit card.
Day's bank account has remained untouched, Price said.
"It's a nightmare of a case," Price said. "He just up and left, and we have no idea what direction he went or if he left voluntarily or not."
Price said the police have already searched Day's ramshackle rural home and property, as well as the local cemetery and canal, even with cadaver dogs. The police are stumped, as they don't know where to look in a vast potential search area containing rivers and woods, Price added.
He also met with county sheriff's deputies and Oregon state troopers to brainstorm ideas for the case, but it didn't help when one of them asked, "What's a Mouseketeer?"
"I wake up every morning with a prayer they will find him and let me know," she told USA Today. "I'm trying to keep him on everybody's mind and spread the word as far as possible, in case somebody somewhere knows something."
Adkins said the frustration is high for Day's family and friends, reported USA Today. Adkins last saw her brother in the summer of 2017, when she visited him.
"He was alert, he was healthy, he was fine," she said. "(Police) are trying to portray him as a reclusive, demented person but in one year's time you can't become that way."
Day is described as being 5 feet, 7 inches tall with gray/brown hair, weighing about 150 pounds. Anyone with information is asked to contact Lr. Jeff Price of the Phoenix Police Department at (541) 535-1113, ext. 309, or the anonymous tip line at 1-888-960-6450.