(KRON) — A young Hayward man is missing after he ran away from an East Bay hospital in the midst of a mental health crisis, his family said.

Dennis Chau, 25, was a patient at John George Psychiatric Hospital in San Leandro. On April 23, Dennis was transferred to San Leandro Hospital for an appointment. Dennis escaped from San Leandro Hospital and has been missing ever since, his brother, Daniel Chau, told NewsNation affiliate KRON4.

The missing man graduated from an Ivy League school, Brown University, and was a Gates Millennial scholar.

His family is now asking for the public’s to help find him. He should be considered an at-risk missing person due to a mental health illness, his brother said. Dennis does not have a phone or money with him because he threw his possessions away during a previous mental health episode, Daniel said.

Family members said they have not been allowed to view any surveillance video from San Leandro Hospital to confirm what went wrong, and how he was able to out-run security guards there. Because Dennis is no longer a patient at John George Psychiatric Hospital, his doctor refused to provide the family with information, Daniel said.

The missing man was last seen in a park in King City, a rural area in south Monterey County, on May 12. Dennis has black hair, brown eyes, weighs 135 pounds, and is 5 feet 6 inches tall.

His cousin, Kyle Ma, told NewsNation affiliate KRON4, “Despite our relentless efforts and the involvement of local authorities, Dennis remains unaccounted for. By sharing his story through your networks, social media platforms, and with local authorities, we hope to widen the search efforts and bring Dennis home to safety.”