The man accused of killing his father last month in Spokane Valley is mentally ill and had been seeing counselors before the killing, his mother said Thursday.

Duy Bui-Nguyen, 30, was vocal and attentive Thursday during his first appearance in Spokane County Superior Court. He’s accused of strangling his father, Huynh Bui, 61, and then beating the corpse for 70 minutes in the family’s garage at 13122 E. Heroy Ave.

The deadly Nov. 29 attack was captured by surveillance cameras, which Bui’s wife had installed because she was concerned about Bui-Nguyen’s recent behavior, according to court documents. Bui-Nguyen was arrested the following day in Seattle, and court documents say he confessed to the crime.

Bui-Nguyen was booked into the Spokane County Jail on Dec. 5 and a District Court judge set his bond at $1 million. Superior Court Judge John Cooney upheld that amount on Thursday.

Bui-Nguyen appeared in court by video feed from a room in the jail. He ended the hearing with a salute and bow apparently aimed at the judge.

Bui-Nguyen’s mother, Nhi Dashiell, was present in the courtroom and said she’s worried about his declining mental health.

“He’s been very sick and we’ve been working on it,” she said.