Begum Kulsoom Nawaz was put on a ventilator after her condition worsened overnight to Tuesday but she did not survive, the family added.
“Begum Kulsoom Nawaz, the wife of our leader, has passed away,” Sharif’s political secretary, Asif Kirmani, said.
Nawaz Sharif was in London with Kulsoom earlier this year when the anti-corruption court handed him a 10-year jail term and sentenced his presumed political heir, Maryam, to seven years in prison over the purchase of luxury flats in London in the 1990s.
The father and daughter left her bedside to return to Pakistan to rally their followers ahead of July 25 elections, which their party lost to the former cricket star Imran Khan’s party.
Both were arrested on arrival and have been imprisoned since.
Family sources said that Kulsoom would be buried in Pakistan.
The government announced that it would help the family “according to the law”.
“We have just received a request from the family, and, God willing, we will be granting parole,” Information Minister Fawad Chaudhry told Reuters.
He said that the former prime minister and his daughter would be freed for 12 hours on the day of the funeral and burial, which is likely to take place in three to four days after the body is flown back home from London.
Prime Minister Imran Khan, army chief General Qamar Javed Bajwa and political leaders expressed condolences to the bereaved family.
“Begum Kulsoom Nawaz was a brave lady,” Khan said in a statement issued by his office.
“She was a brave woman who fought for democracy,” said former president Asif Ali Zardari.
“Pakistan Muslim League – Nawaz (PML-N) and democracy will always be indebted to Begum Kulsoom Nawaz,” Sharif’s younger brother and now president of the party Shehbaz Sharif said in a statement.
Though Nawaz Sharif dominated in politics, his party was in disarray and there were only a handful of leaders and workers left when he was ousted in a coup by former military ruler General Pervez Musharraf in October 1999.
Kulsoom had been at her husband’s side throughout his decades-long political career.
“She was a brave lady,” Siddiq-ul-Farouq, a stalwart party loyalist, told AFP, describing her as well-educated and dignified.
For years Kulsoom stayed out of politics, focusing on the couple’s family and home life.
The couple have four children.
But after Sharif was first imprisoned following a military coup in 1999, she stepped into the limelight, Farouq said.
“She told her father-in-law, ‘Dad, I have to go out,’ and he replied, ‘Daughter, you must go,’” he recounted.
Kulssom took over leadership of the party as president, and held the office until 2002.
She led rallies against the dictatorship with a handful of workers and built a momentum for political activity.
With her husband jailed by Musharraf, she broke through a police barricade set up around her home in Lahore in July 2000 in an attempt to prevent her from leading a public rally.
She managed to get away in a car, which was chased by the police for several miles.
When police finally surrounded the car, she locked herself in for several hours in a stand-off until police finally towed the vehicle away.
The Musharraf regime eventually allowed Nawaz and Kulsoom to leave the country, and they spent years in exile until returning in 2007 to contest new elections after Musharraf stepped down in the face of mass protests.
In 2017, she won the parliamentary seat vacated by her husband in the wake of a Supreme Court decision in a crucial by-election while she was battling cancer in London.
Kulsoom: would be buried in Pakistan.