"There was no Christ in how they treated me," said Mr Sengstock, 58, about Australian Christian Churches and its most prominent entity, the Hillsong Church led by Frank Houston's son, Brian.

"I think Hillsong is nothing but a business."

In Federal Parliament on Monday Prime Minister Scott Morrison refused to say if he tried to have Brian Houston invited to a State dinner at the White House with President Donald Trump in September after earlier dismissing it as "gossip". But he did not deny it.

Mr Sengstock, of Swansea, said Mr Morrison's support for Brian Houston "beggars belief" in the wake of evidence about Mr Houston's failure to report his father's sexual abuse to police and other authorities.

"If Scott Morrison was in front of me now I'd say 'Shame on you. Hanging around with an enabler is a disgrace'," Mr Sengstock said.

Maitland Christian Church Pastor Bob Cotton will release an email this week to more than 1000 affiliated Australian Christian Churches, asking for contributions to support Mr Sengstock as he battles the rare and aggressive cancer, peripheral T-cell non-Hodgkins lymphoma.

Lawyers for Australian Christian Churches denied liability because although Frank Houston was leader of the Assemblies of God in New Zealand in the 1960s and 1970s, he was not in that capacity during the Australian visit. Assemblies of God became Australian Christian Churches in 2007.

Mr Sengstock agreed to discontinue his claim in July, 2018, while struggling with a relapse of his cancer, after lawyers for ACC and the Assemblies of God in New Zealand said they would seek costs against him if he continued to pursue the claim.

Other avenues also failed because of the church's structure, which led Australian Christian Churches to argue individuals dealing with the Frank Houston complaint were not acting on behalf of the church executive.

Mr Sengstock wept when he talked about his wife Lisa, the impact of the abuse on their lives and the future for her if his aggressive cancer follows the predicted prognosis and claims his life.

He gave evidence to the Royal Commission into Institutional Responses to Child Sexual Abuse in 2014 about Frank Houston's abuse and Brian Houston's responses when Mr Sengstock's mother raised the allegations with two other church pastors in 1999.

He used a pseudonym at the commission. He went public in 2018 after the church's treatment of his civil case.

The royal commission found Brian Houston had a conflict of interest when he dealt with allegations about his father in 1999 and 2000, including sending a cheque for $10,000 to Mr Sengstock without advising the church's national executive.

Brian Houston told the royal commission his father "never, ever" preached again after Frank Houston admitted sexually abusing Brett Sengstock, but the royal commission found evidence he spoke at two engagements in Canberra only weeks later.

Frank Houston was allowed to "publicly resign, without damage to his reputation or the reputation of Hillsong Church", the royal commission found.

"Despite Pastor Brian Houston's evidence that he had no doubt that his father's conduct was criminal, he made no attempt to report his father to the police at the time the confession was made to him," the commission said.

It also found Hillsong did not report allegations about Frank Houston to the Commission for Children and Young People, which wrote to the church in August, 2000 that "it is important to remember that any completed relevant disciplinary proceedings must be reported" to the commission, including matters from the previous five years.

He believes the stress of the sexual abuse from such a very young age, that continued irregularly for some time, was a factor in the development of his cancer.

"Frank Houston has destroyed my life. He's completely and utterly destroyed my life," he said.

Brian Houston is a man who heads a church with a philosophy that Brett Sengstock does not recognise or understand.

"My view of what Jesus is like is nothing like their view. Their view is that Christians should be living like kings on earth, but when someone like me needs support they send in the lawyers.

"Trying to deal with a church that does that, it can really send you out of your mind and there's nowhere to go for help. It's just you and them and their lawyers."

Hillsong Church said Brian Houston was overseas but approved the release of a statement saying the royal commission "did not directly involve Hillsong Church".

"The abuse by Frank Houston occurred many years before Hillsong Church existed," the statement said.

"Child abuse is abhorrent but attempting to blame Pastor Brian and tarnish his reputation is not going to advance the cause of any victim."

Australian Christian Churches and Hillsong Church have not yet signed up for the National Redress Scheme.