Two days after being sentenced to life in prison without parole for the murder of his longtime friend Susan Berman, New York real estate heir Robert Durst has tested positive for COVID-19.

According to attorney Dick DeGuerin, Durst is in the hospital and on a ventilator.

“He looked awful Thursday, worst I’ve ever seen him,” DeGuerin said Saturday in a call with NBC News.

Durst, age 78, has numerous medical issues. During his sentencing on Thursday, he was rolled into the courtroom in a wheelchair wearing brown jail scrubs, and had a catatonic stare.

He was convicted in September of first degree murder for shooting Berman point-blank in the back of the head at her home, in December 2000. Durst silenced Berman to prevent her from incriminating him in the reopened investigation of his wife’s 1982 disappearance in New York, prosecutors said.

Durst is the grandson of Joseph Durst, who founded the Durst Organization, one of Manhattan’s largest commercial real estate firms. His father, Seymour, took the reins of the company and later handed control of it to a younger brother, Douglas.

Before Robert Durst’s sentencing Thursday, Berman’s family members addressed the court, describing her as a warm person who’s been deeply missed.

“It has been a daily, soul consuming and crushing experience,” Sareb Kaufman said of her murder. Kaufman’s father was Susan Berman’s boyfriend and he considered himself her son.

Durst’s attorney said he believes Durst has been vaccinated against COVID-19, but could not provide details on whether he had received any booster doses against the virus.

When he saw Durst on Thursday, DeGuerin said, “he was having difficulty breathing, he was having difficulty speaking. He slumped down in his chair… I’m very concerned.”