FORT WORTH, Texas -- The Texas teenager who used an "affluenza" defence in a deadly drunken-driving wreck is expected to waive all detention hearings and stay in jail until turning 19 next month, a strategy that may be aimed at keeping him out of jail at the beginning of his adult probation.

Ethan Couch waived his right to a Friday hearing and "all signs point" to him waiving the subsequent hearings every 10 days that he's entitled to under the juvenile system, said Tarrant County District Attorney spokeswoman Samantha Jordan.

His case will officially transfer to the adult system on his April 11 birthday. Jordan expects a hearing that week to set new terms of his adult probation. Couch could face up to 120 days in jail as a condition of his adult probation.

Although Couch won't receive official credit for the time he's currently serving, legal experts say a judge will informally consider that time, which is why Couch's attorneys may choose to waive all detention hearings.

"They're betting the judge won't put him in jail at the beginning of probation because of the time he's already served," said Denton, Texas, attorney Seth Fuller, who is not involved in the case.

Couch first gained notoriety for the "affluenza" defence -- that he had been coddled by his wealthy parents into a sense of irresponsibility -- after the wreck that killed four people in June 2013 when he swerved off a road south of Fort Worth. Then 16, Couch's blood-alcohol level was three times the legal limit for adult drivers. He was sentenced to 10 years' probation, and the judge's decision not to incarcerate him incited widespread anger.

The teen returned to the spotlight in December after he missed an appointment with his probation officer. Couch and his mother were found later that month in the Mexican resort city of Puerto Vallarta after a phone call to Domino's tipped off authorities to their whereabouts. Couch initially fought deportation, spending a month in a Mexico City immigration detention facility before agreeing to be transferred to Fort Worth.

A judge sent Couch to adult court and back to county jail in February, and ordered a hearing to take place every 10 days while he is behind bars. The first one was to occur Friday. Couch has been held in a maximum-security county jail for nearly a month, in solitary confinement for 23 hours per day. Tarrant County Sheriff Dee Anderson, who has described him as "passive" and "compliant," has said that solitary confinement is for his safety.

Dallas attorney Peter Schulte, who also is not involved in the case, thinks Couch being sent to jail immediately when he turns 19 is unlikely.

"I don't see that happening since he's been in jail for so long," said Schulte. "I think it all kind of depends on how he behaves in juvenile lock-up."

If Couch violates his probation in the adult system, he could face up to 10 years in prison per death.

His attorneys, Scott Brown and Reagan Wynn, did not return phone calls seeking comment.

Couch's mother, Tonya Couch is under house arrest on charges she helped her son flee to Mexico after a video surfaced that appeared to show him at a party where people were drinking -- a violation of his probation. She faces two to 10 years in prison if convicted of hindering the apprehension of a felon. Her next court date has not been set.