Insurance advice

Hi all

A couple of weeks ago my partner was hit by a woman who failed to give way at a slip lane. She is claiming that he’s at fault because she believes he waa racing his friend (he wasn’t, and was only doing around 50km/h when hit)

He got a call from his insurance (RACV) saying that her insurance has put him at fault and now he needs to pay an excess, but in every way possible he just was not at fault. He had 3 witnessed and the accident happened outside of a maccas and 7/11 so there would be plenty of camera footage.

He doesn’t want to pay the excess considering the absolutely was not at fault and he’s finding it incredibly unfair. Is there anything he can do in this situation? What’s the best course of action?