His mother will be at the Anzac Day ceremony on Thursday because he will not be there himself.

And she will bring a burning anger because she feels her son, who had served his country for all his adult life, was badly let down by the military.

In his escalating mental distress after a series of traumatic events, Julie-Ann Finney said her son cried in vain for help.

In despair, he then took the last brutal exit.

"They need to change the way we look after our veterans," said his mother, directing a fierce ire at the Australian military and the Department of Veterans' Affairs.

"They make these men and women. Then they break them. Then they discard them."

Her son was discharged on medical grounds as post-traumatic stress took hold.

He had helped control a fire on board a ship, as well as getting caught in a riot during peacekeeping duties.

And he had been deeply disturbed by naval operations to stop people from arriving in Australia packed on barely seaworthy boats. His mother said these migrants were taken aboard his ship and that affected him deeply.

She said the military had failed in its duty to care for its employee. "I want them to investigate the failures when he was in the service and I want them to investigate the failures once they discarded him," she said.

"And I don't want any other mother to have to tell this story."

Mrs Finney carries a copy of an email to her son from the authorities saying there was no psychiatrist in the ACT at that time taking on new Department of Veterans' Affairs patients.

There was, the email said, a clinic, but a waiting list was in effect until at least April this year - two months after the veteran took his own life.

"He had everything to live for," she said. "He was pouring his heart out to the world. He tried to get to see counsellors but he was knocked back at every turn."

Mrs Finney was at the Australian War Memorial on Tuesday, wearing her son's medals. She will be at the Anzac Day ceremony "to pay tribute to [her] son. He would have been here," she said.

She said veterans were frequently committing suicide and she was campaigning to get more help. If it took a royal commission to help solve the problem, then that should happen.

In his final months, David Finney wrote a blog which reads at times like a howl of pain. His non-military life was collapsing. His marriage had failed.

"I have seen too many broken souls, too many people with no fight left, too many people that can't voice the pain they are in," he wrote.

"I have also seen so many thankful people, people that don't have to say a word when you take their hand.

"I have seen smiles on the faces of kids that are in regions where it looks like happiness is not possible."

And he remembered a previous Anzac Day: "I struggled on Anzac day, to the point I couldn't walk out of my door ... but you keep walking uphill."