As Tessie was organising her husband's funeral, her phone rang. It was her doctor.

On June 16, at the age of 44, John “Sly” Sylvester passed away after a six-year battle with amyotrophic lateral sclerosis (ALS).

In his wake and grieving his loss were his two sons – Gus, 6, and Freddy, 5 – and his wife Tessie Sylvester.

As the Minnesota family pulled together and began organising his funeral, navigating a single-parent family and one pushing on without their “beloved” father and husband, Tessie received a phone call.

“I was literally on the phone with the funeral director, and the other line beeped and it was my doctor, and so I clicked over and answered it. That’s when she said ‘It’s cancer and it doesn’t look good,’” Tessie told CBS News.

It was cancer of an inoperable kind.

“I wasn’t tired, I wasn’t sick, I wasn’t in pain,” she told CBS, flawed at her sudden and terribly-timed diagnosis.

The cancer is called adenocarcinoma, a type of cancer that forms in mucus-secreting glands. The family say it is unclear what the primary source of the cancer is, but it has reached the 36-year-old’s liver and lymph nodes. It’s because of this, she says, surgeons are unable to operate.

Now, a GoFundMe page has been set up for the young family to help curb mounting medical costs, in a bid to buy Tessie some time with her two young boys.

The fundraiser explains that Tessie, as a young woman, spent her time working tirelessly as a dentist for those in low-income communities.

"Tessie worked hard to obtain an academic scholarship to St. Thomas University and later completed dental school so that she could provide a much-needed service in low-income communities.

"For many years she worked as a dentist in a free dental clinic in St. Paul serving homeless and marginalized people, and for the past few years has juggled motherhood, caring for John, and working at West St. Paul Family Dentistry."

Together, the fundraiser writes, John and Tessie "could light up a room with their smiles".

Tessie isn't ready to give in just yet, however, to the cancer that is riddling her body.

“I don’t want to say it’s not fair yet, because I’m not ready to give into it," she told CBS.

You can donate to the family's GoFundMe page here.