Story highlights Prosecutors had asked for a 20-year sentence for Ethan Couch

"There needs to be some justice here," says victims' relative

A defense psychologist reportedly described Couch as a product of "affluenza"

To the families of the victims, Ethan Couch was a killer on the road, a drunken teenage driver who caused a crash that left four people dead.

To the defense, the youth is himself a victim -- of "affluenza," according to one psychologist -- the product of wealthy, privileged parents who never set limits for the boy.

To a judge, who sentenced Couch to 10 years' probation but no jail time, he's a defendant in need of treatment.

The decision disappointed prosecutors and stunned victims' family members, who say they feel that Couch got off too easy. Prosecutors had asked for the maximum of 20 years behind bars.

"Let's face it. ... There needs to be some justice here," Eric Boyles, who lost his wife and daughter, told CNN's "Anderson Cooper 360" on Wednesday night.

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"For 25 weeks, I've been going through a healing process. And so when the verdict came out, I mean, my immediate reaction is -- I'm back to week 1. We have accomplished nothing here. My healing process is out the window," he said.

Lawyers for Couch, 16, had argued that the teen's parents should share part of the blame for the crash because they never set limits for the boy and gave him everything he wanted.

According to CNN affiliate WFAA , a psychologist called by the defense described Couch as a product of "affluenza."

He reportedly testified that the teen's family felt wealth bought privilege, and that Couch's life could be turned around with one to two years of treatment and no contact with his parents.

Couch was sentenced by a juvenile court judge Tuesday. If he violates the terms of his probation, he could face up to 10 years of incarceration, according to a statement from the Tarrant County Criminal District Attorney's Office.

Judge Jean Boyd told the court she would not release Couch to his parents, but would work to find the teen a long-term treatment facility.

"There are absolutely no consequences for what occurred that day," said Boyles. "The primary message has to absolutely be that money and privilege can't buy justice in this country."

His wife, Hollie Boyles, and daughter, Shelby, left their home to help Breanna Mitchell, whose SUV had broken down. Brian Jennings, a youth pastor, was driving past and also stopped to help.

All four were killed when the teen's pickup plowed into the pedestrians on a road in Burleson, south of Fort Worth. Couch's vehicle also struck a parked car, which then slid into another vehicle headed in the opposite direction.

Two people riding in the bed of the teen's pickup were tossed in the crash and severely injured.

One is no longer able to move or talk because of a brain injury, while the other suffered internal injuries and broken bones.

"There is nothing the judge could have done to lessen the suffering for any of those families," said defense attorney Scott Brown, CNN affiliate KTVT reported.

"(The judge) fashioned a sentence that is going to keep Ethan under the thumb of the justice system for the next 10 years," he said. "And if Ethan doesn't do what he's supposed to do, if he has one misstep at all, then this judge, or an adult judge when he's transferred, can then incarcerate him."

Earlier on the night of the accident, June 15, Couch and some friends had stolen beer from a local Walmart. Three hours after the crash, tests showed he had a blood alcohol content of 0.24, three times the legal limit, according to the district attorney's office.

"We are disappointed by the punishment assessed but have no power under the law to change or overturn it," said Assistant District Attorney Richard Alpert. "Our thoughts and prayers are with the families and we regret that this outcome has added to the pain and suffering they have endured."

It is very rare, but not impossible, for prosecutors to challenge the sentence on the ground that it was too lenient, CNN legal analyst Sunny Hostin said.

"To give him a pass this time given the egregious nature of his conduct -- four deaths -- is just incomprehensible," she said.

It is unfair that other young defendants without the same wealth could end up in jail for a lot less, said Hostin, of CNN's "New Day" morning show.

"I think in terms of policy, this really flies in the face of our criminal justice system," she said. "There have to be consequences to actions, and that is what our system is about, even for juveniles."