CALGARY -- The family of a Calgary man who collapsed on the sidewalk in Kingsland when the temperature was close to -30 say he may still be alive if passersby intervened.

Michael Mattern, 43, died in hospital days after falling down and losing consiousness on Jan. 14. According to family, he experienced multiple cardiac arrests and suffered brain damage from the lack of oxygen.

"If he had got things a little faster he may still be here," said Adele Mattern, the man's sister.

Mattern says one woman did stop to help and flagged down vehicles to assist her while waiting for the ambulance, but no one else stepped in.

She believes her brother's needs were brushed off and people assumed he was homeless.

However, her brother lived a nearby apartment with government supported income yet he also dealt with mental health and addiction problems.

"But that wasn't who Michael was. That was something that he struggled with," said Mattern.

"He had a big heart. He was very gentle and he loved his family he always liked to check on how everybody was doing."

Other relatives say assumptions should never prevent someone from lending a hand.

"If life circumstances take people a certain direction it doesn't mean that they're not a great person and that they don't deserve kindness and compassion," said Tammy Lane, Michael Mattern's cousin.

Mattern is survived by his three sisters and his large extended family of several cousins, nieces and nephews.