Amnesty International said in a statement on human rights abuses in Saudi Arabia that Al-Darwish had been held in solitary confinement for six months after his arrest in 2015.
Saudi Arabia, meanwhile, claimed last year that it had abolished the death penalty for juveniles.
According to the Saudi Human Rights Organization in Europe, the country has executed 26 people since the beginning of this year. The total number of executions in Saudi Arabia last year was 27.
In 2019, Saudi Arabia beheaded 37 Shiites and later ousted one of them.