Hazel Houston "went to the Lord" at a Central Coast McDonald's restaurant in early 2004 after an evangelical Christian church service, her husband told Maitland Christian Church five months later in an hour-long sermon.

The recorded sermon challenges Brian Houston's evidence to the child abuse royal commission in 2014 that Frank Houston was "stood down instantly" after admitting child sex offences, and "never, ever preached again anywhere after I confronted him in my office in mid to late November, 1999".

Maitland Christian Church Pastor Bob Cotton, who can be heard on the recording answering Frank Houston's questions, said it was more evidence backing his concerns about Prime Minister Scott Morrison's very public support of Brian Houston, despite an ongoing police investigation into how Mr Houston and the Assemblies of God responded to the Frank Houston allegations.

On Thursday Mr Cotton said Mr Morrison had to come clean about whether he wanted Brian Houston at a White House State dinner in September because "Australians deserve to know the truth".

On Friday Mr Cotton repeated his view that Mr Morrison needed to go to the findings, documents and transcripts of Royal Commission into Institutional Responses to Child Sexual Abuse case study 18 to find the facts about the case of Frank Houston, rather than rely on Hillsong statements.

They would show Mr Cotton and a Central Coast Christian leader were left in the dark about the real reason why Frank Houston suddenly stopped public ministry in November, 1999, and that church leaders failed to tell them Frank Houston was a sex offender of children as young as seven, Mr Cotton said.

In the recording Frank Houston talks directly to young boys in the church, including "This curly-headed young man... what a fetching young fellow he is. Curly hair, sort of. Good looking. It's not your fault you're good looking. Thank God you are. Who wants to be ugly when you can be good looking?"

He also spoke about how he had seen a "significant number of young people who were slain in the Holy Spirit" during "great revivals", where the people "that very often get smitten by the Holy Spirit are young people".

He referred to a 14-year-old boy who had a "revival in his heart" in New Zealand that also revived numbers at Frank Houston's then church.

Mr Houston told the Maitland church he felt "quite nostalgic" but "memory can be a very good thing. It can stir something in you and create desire, which is a step into something God will fulfil in your life".

Mr Cotton said he was horrified to listen to the recording and hear the many direct communications between Frank Houston and boys in the church.

"Betrayal? That's an understatement. I felt, and still feel, gutted like a fish," Mr Cotton said.

His attempts to clarify Frank Houston's status were unsuccessful, he said.

An "extremely confidential" December 24, 2001 statement from Assemblies of God vice president John Lewis to all ordained and probationary ministers noted a "serious accusation" and investigation of a "serious moral failure" claim against Frank Houston, but made no reference to children.

The statement also notes: "We cannot see any reason for this to be announced to your church or further afield".

Mr Cotton said he supported Frank Houston until his death and allowed him to deliver sermons because he believed the "serious moral failure" related to a sexual relationship by Frank Houston, a married man. He said he was "blindsided" when the royal commission in 2014 revealed the extent of church executive knowledge about Frank Houston's child sex offences, and the failure to report allegations to authorities including police.

The royal commission produced documents showing Erina's Coastlife Church senior minister Ian Zema wrote to Assemblies of God national secretary Keith Ainge in January, 2004, seeking clarification of Frank Houston's "discipline and restoration period" after one year of Frank and Hazel Houston attending his church.

"Frank has no desire to preach or for public ministry in any way. However, if he was called upon to pray for someone at the altar or to deliver a prophetic word he is not sure if that is appropriate or approvable by the national executive," Mr Zema wrote.

In late April Mr Ainge said he had spoken to Brian Houston who referred it to the national executive. Mr Ainge advised Mr Zema that Frank Houston was "found to have been involved in serious sexual misconduct and his credential removed with the understanding that it would not be reissued".

"He was also given instruction not to engage in public ministry. Apart from what could be considered 'public ministry', it is up to you as the senior pastor of an autonomous Assemblies of God church to determine the involvement of members of your congregation. The executive would request, however, that you consider this matter carefully in relation to Frank," Mr Ainge wrote.

Despite evidence to the royal commission from Brian Houston and a number of Hillsong and Australian Christian Churches (formerly Assemblies of God) executives about "comprehensive written child protection policies" in place from the 1990s, there was no reference to them in the letter to Mr Zema.

In his evidence to the royal commission Brian Houston said that by 1999, when Brett Sengstock's allegation that Frank Houston had sexually abused him from the age of seven was raised with him, he was aware that "Frank was in the early stages of dementia".

"I am also aware that his memory deteriorated very quickly because of dementia after 2000," Brian Houston said in his statement to the royal commission.

In his book Live, Love, Lead, released in June, 2015 before the royal commission delivered its findings into Australian Christian Churches and Hillsong four months later, Brian Houston said his father "never ministered again" after November, 1999.

"He descended quickly into old age as the shame and torment of his dark past overtook him," Mr Houston wrote.

"Five years later, suffering dementia, he had an apparent stroke in the shower. He fell backwards, hit his head and died," Mr Houston wrote.

"I believe with all my heart that I handled an impossible situation with transparency and honesty."

The royal commission in October, 2015 found Mr Houston had a conflict of interest in his handling of allegations against his father.

Mr Cotton said the one-hour sermon only weeks before Frank Houston's death, aged 82, showed an elderly man who repeated his comments about his wife's death at times, but who also spoke strongly about his faith and responded quickly and firmly to his audience.

"I spent a lot of time with Frank in his final years. I don't agree with the assessment of his mental state that was presented by some to the royal commission," Mr Cotton said.

"Anyone who listens to that sermon would struggle with the idea he was a man suffering from dementia to the extent that he couldn't still deliver a sermon."

During his final sermon Frank Houston thanked the staff and manager of the Central Coast McDonald's where his wife died because they were "so wonderful".

"I found out from the manager that they could not find a McDonald's anywhere where anybody had died. So that's just like Hazel. She had to have the honour of being the first person to go to heaven in a McDonald's restaurant," Mr Houston said.

The McDonald's manager attended the funeral, he told the Maitland church.

Hillsong and the office of Scott Morrison have not responded to requests for comment.