'Cannabis eased my son's suffering. I'll keep fighting for others to have that right.'

In 2010, my happy life as a rural nurse and mother took an unwelcome turn when our third son, Dan, was diagnosed with stage 4 bowel cancer.

From that instant our lives changed, as we struggled to accept the reality that our beautiful son — a previously fit 2o-year-old with a bright future and love of life — was facing at best an uncertain future reliant upon aggressive treatments, and at worst a death sentence.

When Dan first tried cannabis, we had reached a point of utter desperation. He had endured more than three years of continuous gruelling chemotherapy, multiple major surgeries, oncothermia and radiation. Dan battled anticipatory nausea, where just the thought of chemotherapy would cause him to vomit before he had even left home for treatment. To watch this every fortnight as a parent was absolutely soul destroying. He had tried every available anti-nausea medication but nothing worked.

For those who are familiar with the cancer battle, the need to maintain your weight is imperative. Each cycle Dan would lose up to five kilos on chemo week, and spend the next week trying to put it back on before his next treatment. He was depressed and afraid death was knocking at his door.

The cycle of depression became indelibly linked to chemotherapy treatment and made us all feel powerless, so when a former cancer patient suggested cannabis we were ready and willing to encourage Dan to try it, despite our long-held view that it was a dangerous gateway drug. My husband had worked for 35 years in the police force with most of that time in the drug squad — but as we soon found out, watching a loved one suffer is motivation to change entrenched attitudes.

The first time Dan tried cannabis we watched on nervously but with no real expectations. Nothing had worked so far, so we were used to disappointment. But that day was a game changer: Dan started to use cannabis immediately after chemotherapy and he never vomited again. He regained his ailing appetite and maintaining his weight was no longer an issue. He could be at home with his young wife Alyce and, importantly, he regained some power and control over a situation in which he'd previously had none.

Listen: Jane McGrath's best friend Tracy Bevan explains how the McGrath Foundation began. (Post continues after audio.)

What followed was a journey to educate ourselves, and that journey for me is ongoing. The joy of seeing Dan’s suffering relieved was short lived, as we began to confront the reality that we were in fact criminals because of the legal status of cannabis at that time.

That made Dan feel vulnerable, but it filled me with a sense of anger and injustice. This really was a last resort for Dan; it was not about using a recreational drug to get high. It was about giving a dying young man a better quality of life and keeping him at home with family for as long as possible.

The general community overwhelmingly supported us when we went public. I realise now this is largely because so many others were quietly using cannabis to treat a wide range of conditions because conventional medications have failed them. As we spoke out, others gained the courage to do so too. Dan and I met many others, including children with intractable epilepsy. That had a huge impact on both of us and spurred us on.

During that very public campaign media interest was enormous. That's when I met the lovely Helen Kapalos, who worked with us as presenter on Channel 7's Sunday Night program. Helen and Dan developed a bond that was deep and personal for Helen, who had lost her own mum to cancer years earlier.

To my delight and surprise Helen agreed to help me organise the first Australian Medicinal Cannabis Symposium in November 2014. I knew that it was essential to show the policy makers there was science behind the hype and that this was about medicine rather than recreation. During this time, Helen told me she felt the need to follow this story beyond the bounds of commercial television, and she bravely decided to pursue the story further by funding, producing and directing a documentary.

Over a few short weeks, the planning for the Symposium and for the filming of the documentary The Truth about Medical Marijuana took place in my kitchen and over long phone calls with Helen in Melbourne and me in Tamworth.

Dan’s involvement decreased as he grew sicker and sadly he did not live to see the result of Helen’s creative work, nor did he live long enough to see the legislative changes that resulted from his legacy. I know he would be proud, but I also know he would see all this as unfinished business.

Most people choose a path in life that symbolises their personal belief and values, but my path in life was chosen for me. It has taken me on a journey of self-evaluation, education, and included many personal challenges. It has been bitterly sad but Dan’s courage inspires me, and it is surprisingly rewarding to think that many of our sickest and most vulnerable may have the chance for a better life because of his courage.

The Truth About Medicinal Marijuana premieres tonight, Sunday 9 April, at 8.30pm on SBS

UIC 2017 Medicinal Cannabis Symposium will be held in Melbourne on 23, 24, 25 June, 2017. More information available here.