A lawyer for the Canadian journalist, who has been in prison for more than a year on terror-related charges, is expected to ask that the 40-year-old be deported to Canada.
"The deportation is the best hope. This is the only hope," Fahmy's fiancee Marwa Omara told The Canadian Press, adding that a high-level intervention by Canada could help move matters along.
"If Mr. Harper is willing to intervene by himself and call on Egypt to release Mohamed, I think we can still have hope."
Fahmy and his two colleagues — Australian Peter Greste and Egyptian Baher Mohamed — were arrested while working for satellite news broadcaster Al Jazeera English in December 2013.
Their trial, which was internationally criticized, led to a sentence of seven years for Fahmy and Greste, and a 10-year sentence for Mohamed.
An appeal in January led to the announcement of a retrial, but a date was not immediately announced and Fahmy's family was assured diplomatic efforts would lead to his release before he returned to court.
Their hopes soared when Greste was suddenly set free at the beginning of the month under new legislation that allows Egypt's president to deport foreigners convicted or accused of crimes.
Fahmy had already relinquished his dual Egyptian citizenship in December in order to be released under the same legislation and then-foreign affairs minister John Baird said his release was "imminent."
Omara resigned from her job, packed her bags in preparation to travel to Canada and, along with the rest of Fahmy's family, waited every day for word of his release.
An abrupt announcement on Sunday of a retrial date came as a devastating blow.
"This is a nightmare," Omara said. "This means an Australian citizen is worth more than a Canadian citizen? ... How can Canada accept this sham trial."
Fahmy's Egyptian lawyer, who had to scramble to prepare for Thursday's court session, will ask the judge for Fahmy's release, Omara said, and will call for the deportation law to be applied to him. He will also ask for bail, but his family is not expecting that request to be granted, Omara said.
"We don't know what to expect from this trial," she said. "Mohamed will be in a glass cage. This is very humiliating."
Meanwhile, Fahmy's family continues to urge Prime Minister Stephen Harper to call Egypt's president to demand the journalist's release and even launched an online campaign on the matter this week.
A spokesman for the prime minister said Harper had already personally reached out to his Egyptian counterpart on Fahmy's case, though the timing or the form in which that overture was made has not been revealed.
In Ottawa, Baird dismissed critics who say Fahmy might have been released by now had he stayed in the job for a while longer.
"Obviously I don't accept that," Baird said Wednesday. "None of these things resolve themselves as fast as we would like."
For Fahmy's family, however, sufficient action hasn't been taken.
"We trusted the Canadian system, the Canadian government, the Canadian Embassy and they let us down," Omara said. "If Mr. Harper can just call the president and ask him to release Mohamed, I think our position would be definitely better."
More than 49,300 people have signed an online petition demanding stronger Canadian government action and calling its efforts so far on Fahmy's case "weak" and "unacceptable."
The family has been told by Egyptian officials that not enough pressure appeared to have been exerted by Canada.
"They didn't feel that Canada really wants Mohamed out," Omara said. "This is a failure for the Canadian government and for the Canadian Embassy."
The roller-coaster of varying expectations has taken its toll on Fahmy, Omara said.
"He's still strong and he's fighting till the end...but he's very disappointed with how the Canadian government is handling the case," she said. "All what we are asking for is justice."
Fahmy moved to Canada with his family in 1991, living in Montreal and Vancouver for years before eventually moving abroad for work, which included covering stories for the New York Times and CNN.
He took over as the bureau chief for Al Jazeera's English-language channel in Cairo in September 2013.