An 88-year-old man in a wheelchair pleaded not guilty Tuesday to murdering his wife in a nursing home shooting that their family described as a mercy killing.

Roy Charles Laird faces one count of murder with a sentencing enhancement allegation of use of a firearm causing death. If convicted, he faces a maximum sentence of 50 years to life in state prison.

Judge Steven D. Bromberg agreed to release Laird to a round-the-clock care facility with lockdown, noting he doesn't have a criminal record and isn't a flight risk.

"My biggest concern is I don't want you to do anything to hurt yourself," Bromberg told Laird, who said he has been suffering a cold for three weeks and has a dead battery in his hearing aid.

Laird, a great-grandfather who goes by the name "Chuck," will remain in custody on $1 million bail until the judge approves a facility proposed by Laird's relatives.

Police say Laird shot his 86-year-old wife, Clara, during a Nov. 21 visit to the Southern California nursing home and handed over his .38-caliber revolver to authorities after the shooting.

The couple's daughter, who said her father used to visit her mother three times a day after her debilitating dementia and declining health required constant care, has called it a mercy killing.

Laird's relatives declined to speak with reporters outside the courtroom but a family member, Winslow Chase, released a statement saying the case has shed light on the difficulties of dealing with a loved one's mental deterioration with age.

"For those watching a relative make this horrific descent, sometimes to subhuman levels, it's far from an intellectual exercise; it is visceral and gut-wrenching and the source of continual sadness, concern and frustration," Chase said.

Prosecutors have said the murder charge was initially appropriate but could be reduced given the nature of the case. Laird's next court appearance is set for January 24.