The Supreme Court of Canada heard arguments Monday in the case of a Westmount man killed by a falling tree.

Gabriel Rossy, 27, was killed on Aug. 1, 2006 when a 100-year-old tree fell onto his car and killed him instantly.

A coroner ruled the death was preventable because it turned out the tree was rotten.

Following his death, Rossy's family sued the City of Westmount for $1.3 million alleging the city had neglected to deal with this rotting, century-old tree.

The case was initially dismissed because Rossy was in a car at the time of the accident. Because of that, the city was protected by Quebec's no-fault insurance plan.

Rossy's family, however, successfully appealed the decision, arguing that the car was irrelevant to the cause of his death, which was the rotten tree.

"The issue, if I can put it as objectively as I can, is the limit of the term ‘car accident' under the Quebec no-fault scheme. Does it involve things in which the car played a completely passive or incidental role, or does it require a real form of causation? That's the question," said human rights lawyer Julius Grey, who is handling their case.

That question is before the Supreme Court of Canada. It's so far unclear how long it will take the court to render its decision, but it could take several months.