The 'affluenza defense' made him famous, when he drove drunk and killed four people, injured several others, and was sentenced to probation because he was raised so badly as to be completely disconnected from the reality of what he did.
You can read more here and here on his case, which dates back to 2013.
Ethan ran to Mexico with his mother, then was found and returned to Texas to await the next phase of his path to adulthood. There was some thinking that, since he was a minor when he crashed his truck, and was sentenced originally as a minor, that he would continue in juvenile court.
No such luck.
He met his first judge as an adult today, and was told he'd be staying in jail, at least for now, and was sentenced to about two years of time.
That's 180 days for each of the four who were killed in the accident that changed his life, and the lives of the victims who survived, and the families of those who did not, forever.