In what a prosecutor called one of the most unusual murder sentences ever in a Fairfax court, a seriously ill 20-year-old McLean man was sentenced yesterday to indefinite confinement in a Utah state hospital.

Roger B. Judkins, a former Langley High School student who prosecutors said suffers from an extreme nervous disorder, was ordered confined to the hospital after he testified that he shot his father to death Oct. 18.

Circuit Court Judge Thomas J. Middleton's sentence depends on final approval by Utah prison authorities. Three months after the shooting, Judkins' mother and two younger brothers moved back to a former family home near the Provo hospital where the youth will be held.

The youth's father, Newell B. Judkins, a midlevel Central Intelligence Agency offical, was shot to death with a.22 caliber pistol as he slept in the McLean family home.

According to testimony, Roger Judkins walked into the McLean police station a half hour after the shooting, turned over a.22 caliber pistol and admitted shooting his father.

Since then, Judkins has been held in the Fairfax County jail.

Deputy Commonwealth's Attorney Steven A. Merril, who said the sentence was the most unusual he had seen in Fairfax, told the court yesterday that he was willing to suspend a life sentence for Judkins in Virginia because of the man's "physical problems." Typically, persons convicted of murder in Virginia are held in state prisons.

But, Merril added, "It is our recommendation that this defendant never be let on the streets."

After the sentencing, Commonwealth's Attorney Robert F. Horan Jr. said young man could be better treated for his illness inn Utah than in Virginia. Horan said doctors have told him there aren't any specialists to treat Judkins "around here." Prosecutors did not name Judkins' illness.

Under arrangements tentatively worked out with Utah authorities, Judkins will be flown under Fairfax sheriff's guard and at Virginia's expense to Provo, where he will be turned over to the Utah prison system which will bear the cost of his commitment.

Under conditions set by Middleton yesterday, Judkins will never be allowed to leave the hospital, and if he is released, it will only be to return to a Virginia prison.

In court yesterday, Middleton demanded that Judkins explain if he understood wmat was happening to him.

"Ah, it will be a life sentence... and I will be able to go out to Utah," replied Judkins, who sat immobile through much of the proceeding, his hands folded in his lap, his eyes downcast.

According to two family friends, Newell Judkins learned shortly before he was killed that his son was seriously ill.

Burdell Merrell, a family friend and an CIA employe, said yesterday that the young man, whose illness was diagnosed last summer, was not "a wild kid. He is a sick boy. It is important for this to come out now."