An expert testifying in the sentencing proceedings of convicted Parktown Boys' High former assistant coach, Collan Rex, has explained the impact of Rex's abuse on pupils.Child protection and development specialist Luke Lamprecht explained to the South Gauteng High Court, sitting in the Palm Ridge Magistrate's Court, how sexual abuse could affect a child's support system and that of the child's parents and teachers.Denied responsibilityRex was found guilty of 144 counts of sexual assault and 12 of common assault earlier this year.On Tuesday, the court heard how he was exposed to bullying at the school when he was a pupil, and that wrestling and other activities involved the touching of genitals "with the aim of proving that one was not fearful of the other".Lamprecht said Rex's explanation that the touching of genitals was part of initiation and "a Parktown way" did not justify his acts. He added that, by making this excuse, Rex was avoiding responsibility."Based on the bail application, he appears to have denied responsibility by saying this behaviour was "the Parktown way", which also leads to a denial of awareness, and talks to minimisation of the effect of his behaviour on his victims as it is normalised," Lamprecht said.He added that signs of "sexual grooming and power" were clearly seen in a video that was submitted to the court as evidence."It is also clear that he could not have seen this as normal as a secret was maintained," he added. Lamprecht said the videos showed the reality of the experiences the victims endured and witnessed. The court also heard victim impact statements from parents, who described the trauma their children suffered.Most of the statements indicated that victims became aggressive, short tempered and experimented with drugs. SuicidalIn another statement, a parent described how sexual grooming caused her son to become addicted to pornography and play with his younger siblings' genitals. The parents said no amount of remorse could ever take back the trauma they had suffered. They said they hoped Rex would "live to regret the damage he has done" to the victims.One mother said in her statement that her son blamed her for sending him to Parktown. She said the boy once said: "You never sent me to school. You sent me to hell."The parents also indicated in their statements how their sons' behaviour towards females became aggressive because they wanted to "prove they were not gay". Boarding house mother Mariolette Bossert told the court that some of the victims were on suicide watch and that their academic performance deteriorated.She said one of the pupils posted photographs of himself on social media. His eyes were scratched out.After the proceedings, one of the parents told News24 that he was not happy with the way the case has been going. He hoped a harsh sentence would be imposed."Look, there's a lot we are not happy about from the State and the judge, but we will see what happens," the father said.On Thursday, the State and defence are expected to present their closing arguments before Judge Peet Johnson determines Rex's sentence.