Abdullah Morsi's body buried at night, amid tight security
The body of Abdallah Morsi was released from the Cairo Zeinhom morgue late on Thursday, after a funeral prayer in absentia was held for the 25-year-old.
Abdallah's brothers, Ahmed and Omar, accompanied their mother Najla Mahmoud, who took the body to its final resting place, alongside their father who passed away earlier this year.
Egyptian authorities warned the family against a large congregation at the time of the burial, sources close to the family told The New Arab.
Abdallah died on Wednesday night in Cairo, after suffering a fatal cardiac arrest while at the wheel of his car.
"A friend who was with him was able to stop the car and take him to hospital", the family lawyer Abdel Moneim Abdel Maqsoud said.
Mohamed Morsi - who as Egypt's first freely elected president headed an administration loyal to the now banned Muslim Brotherhood until he was deposed by the military in 2013 - died in court on June 17.
The military overthrow of Morsi was led by Abdel Fattah al-Sisi, who ascended to the presidency in 2014 polls, before securing an official 97 percent in elections last year.
Mohamed Morsi, 67, collapsed during a court session in Cairo, some six years after his ouster and imprisonment.
He had been sentenced to 45 years in prison for offences including "inciting violence" in late 2012 against protesters and "spying" on behalf of Qatar.
Sisi has stifled opposition, particularly from the Muslim Brotherhood.
Egypt declared the Brotherhood a terrorist organisation in late 2013.