Facing a Brisbane court the day before his 50th birthday, a tearful Gregory Jason Krause pleaded guilty to one count of assault occasioning bodily harm, with a charge of unlawful striking causing death dropped by prosecutors.

The word tragedy is often overused but can be applied to the circumstances of Krause’s offending on February 24, 2020, Brisbane Supreme Court Justice Martin Burns said on Wednesday.

That day Justin Krause arrived at the family home at Nanango, northwest of Brisbane – where the brothers’ parents, sister and her daughter also lived – after staying with friends for days and probably using meth, the court was told.

He was agitated when he later emerged from his bedroom and abused his sister and her daughter.

“It was vile abuse, particularly the abuse directed to a 14-year-old girl,” Justice Burns said.

Krause heard it from his bedroom and came out, telling his brother to get out the house.

He walked back to his room, but his brother followed.

The pair got into a struggle during which Krause was struck on the back of his head.

His brother fell, smashing into a glass cabinet, during the wrestling that followed.

Krause was pulled away by his father, but kicked his brother – who was on his hands and knees – once in the face before both men walked away.

Justice Burns said photographs suggested Krause used “considerable force”, with a scan the following day revealing his brother had fractured nasal and eye socket bones.

Justin Krause’s condition deteriorated and he went into cardiac arrest in hospital the day after the assault.

The Crown dropped a charge of unlawful striking causing death on Wednesday after a medical expert provided evidence that the blow, if anything, could only have been a minor contributor.

Justin Krause had a “constellation of serious medical issues, not the least of which was a severe drug addiction”, Justice Burns said.

Krause had been struck with remorse on hearing his brother died, and suffers from anxiety and depression.

But he was told there could be no excuse for kicking someone on the ground.

“It’s a cowardly act, but what is in your favour is that you did not persist with the act,” the judge said.

He accepted Krause’s action was spontaneous and probably a reaction to first being hit from behind, but said this did not change the gross and unnecessary over-reaction.

The court heard Krause’s criminal history was mainly for drug and dishonesty offences, but he was also sentenced in 2003 for committing aggravated robberies with two of his brothers while a drug addict.

Krause was sentenced to two years behind bars, but was immediately released on parole having spent 259 days in custody.