On Monday, he began a hunger strike against his detention and the government's crackdown on opposition activists.
Allema Khan said after visiting him on Wednesday: "Imran is not taking any liquid and he is not eating. He has grown weak, but his spirits are very high."
"He chided us for showing weakness and he said we should urge the youth of Pakistan to go on a token hunger strike to press for the restoration of the judiciary," she said.
The Pakistani authorities have denied Khan, who is the only MP that his Movement for Justice party has, is on hunger strike and say he has been eating regularly.
Meanwhile, senior government officials said that Musharraf could quit his post as chief of the army and take the presidential oath as a civilian as early as Saturday.
"It may happen on Saturday," Malik Mohammed Qayyum, the attorney-general, told the Associated Press. "I know the president, and he will honour his commitment."
The supreme court is expected to clear the last legal obstacles to his continued rule as president on Thursday, paving the way for the election commission to confirm his victory in a disputed presidential election.
Benazir Bhutto, a former prime minister and opposition leader, said on Tuesday that it would be a "good sign" if Musharraf left his army post, but that her party needed a few more days to decide whether to contest parliamentary election planned for early next year.
However, the court decision is unlikely to prevent further criticism of the situation in Pakistan as it will be made by a supreme court that Musharraf purged of dissenting judges.
Police have stopped Wajihuddin Ahmed, who ran against Musharraf in the election, from visiting Iftikhar Chaudhry, the former chief justice, and other sacked judges under house arrest.
"We want restoration of superior judges and removal of all existing judges. They are not judges, they are dummies," Ahmed said, as police stopped him and a dozen lawyers.
Saudi Arabia visit
Also on Wednesday, the president returned from a visit to Saudi Arabia, which Pakistan's media suggested had been made to reach out to Nawaz Sharif, another former prime minister who lives in exile in the kingdom.
Sharif told the Reuters news agency that Musharraf's go-betweens had made several attempts to arrange a meeting in recent months, but had not contacted him during the president's visit.
"Perhaps things will be clearer in a day or two," he said. "Pray that I can come back to Pakistan. I want to come back to my country."
Sharif, who Musharraf replaced after a bloodless coup in 1999, attempted to return to Pakistan in September only to be put on a flight back to Jeddah.