Erica de Belin told jurors her brother, who is her best friend, was "caring", "empathetic" and "generous".

She said her brother was a "walking enigma" because he was a "100kg rugby league player" who did yoga, meditated, and practised daily gratitude.

Ms de Belin, who gave evidence via video link from England, told the Wollongong District Court about a story of her brother helping an old woman with arthritis by mowing her lawn.

"I think anybody who has spent any time with him knows how good a person he is," Ms de Belin said. "Being a professional athlete is only small part of who he is.

"It has been an honour and privilege to see him become a father."

De Belin's lip was quivering during much of her evidence before he broke down and loud sniffles could be heard throughout the courtroom.

The NRL player, 29, and his friend Callan Sinclair are in the third week of their NSW District Court trial in Wollongong over allegations they jointly raped a then 19-year-old woman in a North Wollongong apartment. They have pleaded not guilty to five charges of aggravated sexual assault, claiming the threesome was consensual.

Brian Johnston, the former chief executive of de Belin's club St George Illawarra, said the footballer was always willing to welcome new players.

Mr Johnston told the jury de Belin, who has been a Dragons player since 2011, had shown "loyalty" to the club and had represented the organisation at school, charity, community and media events. He said he had never received any reports of incidents apart from this case, and noted de Belin had never been sent off the field, labelling him a "role model" within the club.

The trial continues.