I had a reply posted, and then I realised I was recommending people on the wrong side of the country.
There is Dr. Anthony Chaffee in Perth. Strictly speaking, he is a neurologist, but he does have a side practice treating patients with a low-carb, even carnivore diet. I don’t know how well-connected he is, since he’s an American, but if your friend is too far from Perth, his office might know of someone closer.
As a last resort, you could ask Peter Brukner, Paul Mason, or Gary Fettke if they know anyone in W.A., but the first two are in Melbourne, and Dr. Fettke is in Hobart. But they are well-known for using a ketogenic diet in their practices, so might very well know similar doctors in W.A.