The Supreme Court only prevented him from getting the death penalty, he’ll still get life in prison, and at his age, he may be there over sixty years.
As I understand it, Life in Prison without the possibility of Parole is off the Table if you are a Minor.
He is also eligible for parole at some point.
Miller v. Alabama, 567 U.S. 460 (2012), was a United States Supreme Court case in which the Court held that mandatory sentences of life without the possibility of parole are unconstitutional for juvenile offenders.