My mother bore four children. I was the oldest. And for four years I was an only child. Then came my sister, and two years later our brother. When I was thirteen our  youngest brother was born. I was given ample opportunity to discover first-hand what raising a child required. My mother was busy and she delegated some of the tasks in looking after a baby to me, her oldest child.

It's a long time ago. I don't think I ever hesitated, nor did I mind. After all, I was away at school for much of the day and it would only have meant changing diapers occasionally and looking after him from time to time. A year later I met the boy who would become my husband. And of course my brother was just a year old. Among other things we would walk my brother in his stroller.

Much, much later, when I was a young mother and my young brother became a  university student -- the only one among us who attended university -- he commandeered a bedroom on my parents' third floor of their house which had a strange little alcove with windows and he began to grow quite beautiful plants there. He also kept a reptile menagerie in the basement of the house.

It was a tossup, it seems, whether he would become an animal biologist or a botanist, and in the end, though at one point he added an in-house raccoon to his household pets, he decided for plants. I didn't know it at the time since I was no longer living at home and hadn't been for years, but the plants were marijuana plants. There was one time when he told me he'd like to introduce me to cannabis use so I could get 'high'. I laughed and informed him I was always high.

I meant I needed nothing to induce me to be happy with life. I had my husband, my companion in life, my love of loves and we had three very young children together. When my brother graduated from University of Toronto he was offered a teaching position in Halifax at Dalhousie. He remained at Dalhousie, a professor of botany throughout his professional career. He retired at age 65.

Which is when he was diagnosed with end-stage stomach cancer. He was an outdoor enthusiast. A birder, travelling abroad to see exotic birds. He regularly played squash, an energetic game if ever there was one. He was in good health, and remained curious about life. He signed on to ocean cruises as an in-house science adviser to entertain cruise guests and enjoyed it. And he never stopped using cannabis, regularly and frequently. He had been a vegetarian for many years.

After his diagnosis he went directly to waiting and palliative care. He experienced no pain, no symptoms of cancer, nothing that might have alerted him that something might be wrong. It was a casual, infrequent medical examination that revealed the cancer that had spread beyond the capacity of medicine to surgically remove. He was given chemotherapy and radiation to extend his life. The cancer kept spreading. He tried to be stoic. None of us can believe that life is about to end.

He did suffer. Mental anguish. Regret, misery that his life was in its end stages. He did not become reconciled with impending death.

Cannabis is now legal in Canada. Happy news for many. My brother would have celebrated and snorted "about time!" But not that much is known about long-term effects of cannabis use. The science quite simply isn't there. No research of any real value, it appears. So it is an unknown whether it really is good or not to consume or smoke cannabis with its cocktail of substances.

One of my cousins was also an inveterate marijuana user. He kept himself in good shape. He was another individual conscious of good health equalling quality of life. He too lost his life to cancer at a relatively  young age.

Science does know some things about cannabis and when it is counter-indicated. But long term use? Everything in moderation, needless to say; a formula of long-standing and one that no sensible person would argue with.

It's likely that marijuana was a comfort to my brother in his final weeks and days of life. But perhaps it is also possible that marijuana did him no favours.