Mr Calder was just 33 years of age and leaves behind a partner, Andrea, and three young sons – Thomas, Harry and Gus.
According to newspaper reports, Mr Calder began suffering headaches before being admitted to hospital, where he passed away on July 11.
Belle Property declined Real Estate Business' invitation to comment. However, Mr Calder’s partner, Andrea Young, who worked alongside him at the Ascot office, described him as an “amazing family man” and said he was utterly dedicated to their three sons.
Speaking with Brisbane’s The Courier Mail, she said: “The situation is just dreadful but I have to be strong.”
Ms Young said the three boys – aged four, six and eight – were coping relatively well with their father’s sudden death.
“I had to be honest and upfront with them," Ms Young said. "They have their moments and say ‘Daddy’s dead’. It’s been a whirlwind for all of us.”
The newspaper report said Mr Calder had sold property for eight years before opening Belle Property Ascot in 2012. Ms Young indicated the business would continue in her late partner’s memory.
“Michael was always happy. He always had a smile on his face and loved high-fiving all the kids at day care,” Ms Young said. “His drive and excitement for everything is unforgettable. He was so full of confidence.”