William Rawsthorne was just 17 when he died last month, and in his death, his donated organs saved four other lives.

He didn't judge people by how they looked; he was kind, a gentle giant who loved computers - but for the last decade he struggled with a suspected, but undiagnosed, complex personality disorder and fell through the cracks in the system.

"All I'm going to say is when I needed the funding it wasn't there, making people jump through a million hoops to get it is not the way to go," reads the last text he sent.

"I'm not blaming you, I just want you to use this opportunity to push for easier access for the funds that is needed. I thank you for everything you did behind the scenes to help me [named removed]."

At seven, Will started to show aggressive behaviour toward himself. He would run out in front of cars and wanted to take his own life. By nine, he would have blow-ups at school and was excluded from a lot of the normal activities that kids his age enjoyed.

Episodes grew so violent that the police would have to be called and efforts to have him admitted to a child and adolescent mental health ward were rejected because he wasn't considered "high risk" enough.

Without a proper diagnosis, Ms Hunt said her son was denied funds from the NDIS and had limited access to psychologists or counsellors.

Challenge Community Services were one of the only ones that helped, and Ms Hunt said she's determined to create change in a system that is broken.

"I wonder what would have happened if we just got the help at the beginning that we needed," she said.

"I've thought about all the things he has been robbed of in his life and that frustrates me and it hurts me and it makes me angry, but most of all it makes me want to not let any other parent have to go through this."

As a single mother of four children, Ms Hunt struggled to manage her son's outbursts and increasingly they grew worse.

There were good days and bad days, for every step the family took forward there would often be more steps back.

The closest she came to help was 18 months of therapy at Dean House, but after an episode at school it was suggested Ms Hunt involve the Department of Communities and Justice (DCJ).

"In the process of that, DCJ said he's not coping and took him away," she said.

"For three years in court I fought to get Will back.

"As a last resort I did that, and I felt like I was a failure as a parent to reach out to DOCS [DCJ] for help, I wanted to provide the best for my boy and they took him."

Will then bounced through about 16 different placements, seven caseworkers and came back with "two bags of damp, mouldy clothes," Ms Hunt said.

Unable to get help without a diagnosis, there were days where Will struggled to get out of bed and even mental health hotlines would put him on a wait list.

Now, the family has started the Will I Am Legacy fundraiser for Challenge Community Services, and Ms Hunt wants politicians and change-makers to hear Will's story.

"We all matter, or we should to the people sitting behind those desks in Canberra," she said.

"My frustration is with the politicians, mental health doesn't take weekends or public holidays - it doesn't work 9 to 5pm.

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"We don't have the services for these people, they talk about COVID-19 being a pandemic, our next one will be this if people don't wake up and talk about it."

Challenge chief executive Peter Maher said Will was a valuable member of the community who would be greatly missed, and expressed condolences to his loved ones.

"We are incredibly thankful for the generosity of Will's family in donating the proceeds of their fundraiser to our 'School's Out' program in Tamworth," he said.

"As part of our program, Will attended mentoring nights, and received emergency respite in addition to one-on-one support.

"The program offers young people living with mental health a safe environment to relax, open up and feel supported."