Extradition of the infamous “affluenza teen” Ethan Couch could be months away, according to his new lawyer Fernando Benitez.

US authorities hoped to have Couch,18, in custody as early as Thursday but the teen’s lawyers won a stay of deportation late last week. It could now take months for Couch to be deported back into the US, Benitez told WFAA, an ABC affiliate in Texas.

Couch came into the national spotlight in 2013, after his lawyers argued that a condition of “affluenza” in part led him to kill four people in a drunk-driving accident. He was 16.

Having been raised by wealthy parents, Couch never learned the difference between right and wrong, they argued. They added that he did not understand the consequences of his actions. Couch ultimately pleaded guilty, and a juvenile court judge sentenced him to rehab and 10 years probation, rather than the recommended 20 years in prison.

Under the terms of his probation, Couch was not allowed to drive, drink or take drugs. In early December, a short video surfaced alleging that he had violated the terms of his probation by drinking. Even though the authorities have yet to publicly confirm that Couch was the man in the video, he and his mother, Tonya Couch, promptly fled to Mexico.

After Couch failed to meet with his probation officer in early December, local authorities in Texas issued a warrant for his arrest. Eleven days after FBI and US marshals joined the hunt, officers arrested the teen in the resort city of Puerto Vallarta, where a Domino’s pizza delivery tipped them off. Couch and his mother were detained on Monday 28 December.

American authorities said that Couch and his mother entered Mexico illegally and therefore should be returned to the US. A judge at the Mexican immigration court will hear Couch’s case and afterward will have 90 days to make a ruling.

Benitez argues that kicking Couch out of Mexico would violate his rights.

“He hasn’t committed a crime in Mexico,” Benitez told WFAA. “Why would Mexico go along with this idea of locating someone and summarily kicking them out of the country so the marshals can grab him across the border? I don’t think that’s OK.”

The matter of Couch’s deportation will take at least two weeks to resolve, according to Richard Hunter, chief deputy for the US marshals service in south Texas.

“It also depends on the fact the Couches have legal counsel. And it seems to me, if they wanted to, they could pay them as much money as they want to drag this thing out,” Hunter said on Wednesday. “We’re hopeful that’s not the case. We’re hopeful the Mexican immigration court will make a quick and decisive decision and return the Couches to America.”

Benitez, however, has other plans.

“From the hearing, a judge has up to 90 days to issue a ruling. After that, we could appeal a decision. We’re going to take this to the full extent of our capacity and have whoever needs to review it,” he told WFAA.

While Couch awaits his fate in Mexico, his mother returned to the US on Thursday and remains in custody in Los Angeles.

She has been charged with hindering her son’s arrest and faces between two and 10 years in jail. Her bail has been set to $1m, which she will be allowed to pay on arrival in Texas.