The Thursday verdict was immediately condemned as politically motivated - an attempt to silence a woman who focused world attention on terrible human rights abuses in the central Asian republic.
Mirzahaim Avazov said the verdict against his 62-year-old mother, Fatima Mukhadirova, was "unjust and slanderous".
"The law is used only to protect this country's despotic regime, not to protect the people," he said.
The former Soviet republic's secular authorities launched the case against Mukhadirova after allegedly finding leaflets published by Hizb al-Tahrir - a non-violent Islamic radical organisation that has attracted grassroots support.
Since the Soviet Union's collapse, President Islam Karimov has attempted to crush even moderate Islamic belief among Uzbekistan's mostly Muslim population, fearing destabilisation from neighbouring Afghanistan.
"The law is used only to protect this country's despotic regime, not to protect the people"
son of jailed Fatima Mukhadirova
But during the trial, Mukhadirova said the authorities were prosecuting because she publicly sought redress for the death of her son, Muzafar Avazov, who died at a notorious desert prison camp housing political prisoners in 2002.
"She's been convicted because she tried to protect her children - she was trying to stop what happened to Muzafar from happening again," said Lazokat Avazova, whose husband is also serving a jail sentence also for religious extremism and threatening the state.
The fate of Avazov and fellow prisoner Husn al-Din Alimov, allegedly also boiled to death, attracted international attention last year when Britain's ambassador to Uzbekistan Craig Murray raised the alarm.
Murray commissioned a report by a Western forensic expert who found that photographs of the two men's corpses appeared to support the claim that they had been beaten and then boiled to death while at the Jaslyk prison camp.
However the British Foreign Office investigated the ambassador's activities in an attempt to normalise relations with the host country.