Thousands of mourners filled a conference centre in Mississauga, Ont., Thursday morning to pay their respects to Apotex founder Barry Sherman and his wife Honey, who were found dead in their home nearly a week ago.

Following opening prayers that began at about 11:30 a.m. ET, the couple's four children stood together as son Jonathon paid tribute to their parents.

"This has been so incredibly painful and so bizarrely surreal," he said through tears.

He thanked their family and friends for their support, noting that after the "condolences started flooding in, so did the bagels," to laughs from the crowd.

He honoured his parents' zest for life that they loved to share with others, adding how successful they were at life as a unit.

"You were like a lock and a key: each pretty useless on your own. But together you unlocked the world for yourselves, and for us and for so many others."

He also announced the creation of a foundation in his parents' name: The Honey and Barry Foundation of Giving, which they have asked an aunt to oversee.

Barry and Honey Sherman who were found dead from strangulation in their Toronto home last week. (United Jewish Appeal/Canadian Press)

'It's such a shock'

Prime Minister Justin Trudeau, Ontario Premier Kathleen Wynne, Ontario Health Minister Eric Hoskins and Toronto Mayor John Tory were among the thousands in attendance.

Tory told mourners he was "profoundly saddened" by the deaths of the Shermans, and paid tribute to their dedication to bettering their city, and their country.

Long before he was in politics, Tory would ask the couple for support for various charitable projects, "and rarely if ever went away without some support," he said.

Wynne urged mourners to follow the Shermans' example: "May we all be inspired to live as they did. Full of compassion, hope and generosity."

'Our hearts are broken'

About 7,500 chairs were set up at the International Centre in Mississauga, a venue usually reserved for large trade shows and conferences, and all appeared to be full. Mourners were lined up hours before the service began.

"He was like a father figure, so humble, sweet, dedicated," Apotex employee Lance Myers told CBC News before the service. "It's such a shock."

Thousands of employees of Apotex, the generic pharmaceuticals giant that Barry Sherman founded, were expected to attend the service after the company announced plans to shut down its global operations for the day.

Apotex president and COO Jack Kay, his voice breaking numerous times, reminisced about 35 years of both a business and personal relationship with Barry Sherman and his family. In 1982, Sherman interviewed Kay in Montreal for a vice-president's job at Apotex, and ended their conversation by saying: "Come move to Toronto and we will build this company and have a lot of fun and make a lot of money."

He noted Sherman's vast intellect, devotion to hard work and love of his family and friends.

"Barry was just a regular guy," Kay said. "He was kind of a teddy bear in real life, but with a mind like a steel trap and the stubbornness of a bull. He changed my life, and I'm so very grateful to have shared those years with him."

Joel Ulster, who called himself Barry Sherman's oldest friend, described him not only as "the smartest person, but much more importantly, he had the biggest heart."

The Shermans not only gave millions to charities, he noted, they also helped many people quietly and privately, he said.

"Our hearts are broken."

Mary Shechtman speaks during a memorial service for sister Honey Sherman, as a family member wipes tears from his eyes, on Thursday. (Nathan Denette/The Canadian Press)

Sen. Linda Frum, said it was "a privilege" to call the Shermans friends, and reminisced about Honey Sherman's kindness. They first met on a trip to Israel at a time when Frum was a nervous flyer. Though they barely knew each other, Sherman arranged to sit next to Frum so she could help calm her nerves. On the many subsequent flights they took together, Sherman would be engrossed in a newspaper "but she would stretch out her hand for me to hold," Frum said.

"It was easy to love Honey and everybody did."

Honey Sherman's sister, Mary Shechtman, tearfully recalled how her relationship with her sister was marked by two favourite things: laughing and shopping.

Shechtman regaled mourners with a tale of having hurt a leg while they were skating as youths. "Keep skating," Honey kept admonishing her. Eventually, it was revealed that Mary had a broken leg.

The phrase "keep skating" became a running joke between them when encouraging each other to persevere.

"She just wanted to make everybody happy," Shechtman said through tears. "She wanted to give everything to everybody."

Sen. Linda Frum speaks during the memorial service for Apotex billionaire couple Barry and Honey Sherman. (Nathan Denette/The Canadian Press)

Organizers said the outpouring of support for the billionaire philanthropists necessitated the move to the larger, non-traditional venue.

"The response has been huge," said Michael Benjamin, director of Benjamin's Park Memorial Chapel, which co-ordinated the service. "I don't think there's been this kind of a horrific tragedy that's faced this community before."

"It gives us a lot of comfort that so many people loved them," Avi Benlolo, chief executive of the Simon Wiesenthal Center for Holocaust Studies in Toronto and a friend of the Shermans, said Wednesday.

"They wanted to help everybody, they wanted to be there for everybody," he added.

More than 100 people also volunteered to work at the funeral, organizers said.

Forensic investigators can be seen exiting the Shermans' home on Thursday. (John Lancaster/CBC)

Police still probing 'suspicious' deaths

Sherman, 75, and his wife, 70, were found dead in their Toronto home last Friday.

Toronto police say the couple died of strangulation, and investigators, including some from the force's homicide unit, are treating the case as "suspicious." Police have said they are not searching for any suspects in the case.

CBC News has learned that the Shermans were found near the pool in the basement of their home. Investigators have found no security cameras inside or outside the home.

In the days since, the Sherman family has blasted "rumours" circulated in the media about how the Shermans may have died, including the possibility of murder-suicide or a double suicide.

"We are shocked and think it's irresponsible that police sources have reportedly advised the media of a theory which neither their family, their friends nor their colleagues believe to be true," said the Shermans' children in a statement last weekend.

CBC News has not reported any unverified details of the investigation.

The Sherman home, on Old Colony Rd. in Toronto, was up for sale at the time the couple died. (Evan Mitsui/CBC)

Online messages stream in

Hundreds of people have left messages for the Sherman family on condolence pages set up by Benjamin's Park Memorial Chapel and the United Jewish Appeal of Toronto.

Covenant House executive director Bruce Rivers was among those to have left a note to the family, despite never having met the couple in person.

For the past three years, the Shermans and Apotex donated prescription and non-prescription drugs to the street kids served by his organization.

"The way they've given back to the community, it's critical that we step up as an organization to speak out," he said. "That's why we wanted to post and that's why we'll be present [at the service]."