The information you need to obtain a Certificate of Validation is
HERE.
I suggest your friend commence applying for an Australian
Certificate of Validation at least one or two years ahead of his planned visit and expect to be frustrated by professionals. I haven't read the current requirements but will probably to require a Certificate of Competency in English, a Class 2 Medical Certificate from a CASA approved Doctor, an ASIC Card and he may find birth certificates from at least five generations of antecedents also helpful.
We can't have these unqualified foreign pilots flying in our Aussie air space!!
