Edmund Bascom, 65, was found by a Santa Clara County Sheriff's deputy and taken to a local hospital, Sgt. J.D. Nelson said.
Bascom was the last patient unaccounted for from Valley Springs Manor, a facility at 17925 Apricot Way in Castro Valley with a string of violations that led the California Department of Social Services to suspend its license, effective Oct. 24.
County authorities have said around 14 sick and elderly patients were abandoned at the facility that date, when most of the staff walked out.
A few staff members stayed behind to help care for the remaining patients, but those staff members quickly became overwhelmed and called for help on Sunday, Oct. 26. Paramedics and sheriff's deputies removed the patients that day.
Bascom was last seen at the San Leandro BART station at 2:06 p.m. Friday Oct. 25, according to Nelson.
He has gone missing many times in the past and always turned up safely, Nelson said. But the case highlights the problems that led to the facility's closure, which included understaffing, untrained staff, mix-ups in medication, safety violations and poor maintenance and hygiene.
A criminal investigation is under way to see if the facility's operators committed elder abuse or other offenses but the investigation will be lengthy and no arrests are imminent, Nelson has said.
In addition to the sheriff's department, agencies that will participate include the state Department of Social Service's community care licensing unit, the elder abuse section of the Alameda County District Attorney's Office, the California Department of Justice's Medi-Cal fraud unit and the FBI's health care fraud unit, according to Nelson.
According to a complaint filed by the state, the facility's operators are Herminigilda "Hilda" N. Manuel and Mary Jullead N. Manuel. Nelson said the investigation "will take a long time" because authorities are going through voluminous documents they recovered when they got a search warrant and went to the facility on Saturday.
Among the documents are patients' medical records, employee records and various facility records, he said.
Nelson said when authorities went to the facility on Saturday the conditions "weren't completely terrible" but the home was "unkempt" and "not what you would expect" at a care home.
A spokesman for the Department of Social Services said after the facility was shut down by local authorities that state regulators were aware of the issues at the home but understood that patients would be cared for until alternate facilities could be found for them.