Cantwell, who raced with the Jittery Joe's, Fly V Australia, Saxo Bank and Drapac teams during his career, "lost his battle to mental illness", according to the Go FundMe page, on November 6.
"We would like to ask you for your generosity to help us secure some financial stability to his kids during this period of adaptation and mourning. This money will go towards rent, utility bills, education and some much needed psychological support treatment for the kids," the page states.
In 2017, Cantwell wrote about surviving testicular cancer on his Facebook page, revealing that he had undergone surgery to remove a 4.5cm tumour and went through rounds of chemotherapy before being declared cancer free.
Last month, Cantwell recalled the death of his brother on his page: "A year ago today I lost my only brother to mental illness as he followed in my father's footstep. I'm so so sorry I was not there or did not know the pain you were going through for you to make this decision. Your smile, guidance and love is missed more than you could ever imagine. The hole that I and the rest of your family have to live with now is almost unbearable."
The GoFundMe post says that part of the funds raised will go to support suicide prevention.
"Through this page, we not only want to support his kids and their mother, but also bring light to the suicide epidemic that Australia and the world faces today - especially amongst men. According to the Australian Bureau of Statistics, in 2017, 3,128 people died from suicide being 75% by males."
The fundraiser at the time of publication had already raised over $15,000 in 16 hours.