The family feud over the status of the text played out in the Queensland Supreme Court as the man's brother and nephew asked for the message to be treated as his final will.

The 55-year-old man took his own life in October last year and the unsent text message was found on his phone the following day.

He wrote that his brother and nephew should "keep all that I have house and superannuation, put my ashes in the back garden".

He said his wife should "take her stuff only she's ... gone back to her ex AGAIN I'm beaten".

The man gave his bank details before signing off "my will" with a smiley face.

The man's widow, supported by his son from a previous relationship, argued the text message should not be treated as his final will.

In a judgment delivered on Monday, Justice Susan Brown said the woman "particularly attaches significance to the fact that the deceased did not send the text message".

This, she argued, was "consistent with the deceased not having made up his mind".

Justice Brown said it was "uncontroversial" that the relationship between the couple, who had been married for a year and in a relationship for three years and seven months, "had problems" and the wife had left on at least three occasions.

"It should be said, notwithstanding that the applicant had moved out, she still made arrangements to take the deceased to his mental health appointments and that they spent the weekend prior to his death together, cleaning garden clippings and boxing books for Lifeline," the judge said.

While it was not necessary to make a finding on this point, Justice Brown also said the evidence before her did not establish that the woman had returned to her ex-husband or had any relationship with him "other than one of friendship".

She said "the informal nature of the text" did not exclude it from being treated as representing the man's intentions and noted a 2013 Queensland case in which a DVD marked with "my will" was found to constitute a valid will.

Justice Brown took into account a range of factors in ruling the text message was a valid will, including that it was "created on or about the time that the deceased was contemplating death, such that he even indicated where he wanted his ashes to be placed".

The judge added this ruling would not stop the man's wife and son making an application under family provision laws for a share of his estate, which included a house and superannuation account.

The courts in recent years have grappled with unusual cases involving informal wills. In 2015, the NSW Supreme Court ruled a video will was valid and displaced a written will made just two days earlier.

Justice Geoff Lindsay said at the time that he understood "the court had never before admitted a video will to probate".