It's clear that he made no attempt to use the weather radar. Had he done so, with correct technique, he'd have know exactly where he was.
The following extracts from Peter Mahon's book "Verdict on Erebus" page 168, answers your accusation that "it was clear he made no attempt to use the weather radar"
" The Bendix company (weather radar) opinion was that because the slopes of the mountainside were covered in snow and ice which was totally dry, then the return from from the mountain would be nil. Even though this particular radar equipment was programmed only to detect moisture, it would nevertheless give a return off high terrain composed of rock and earth, but a thick coating of dry snow and dry ice on the northern slopes of Mount Erebus would cause the radar beam to be totally absorbed and make it impossible for any return to be received. This opinion was based upon the inability of the radar pulses from the radar to achieve any return once they penetrated the crystalline structure of dry snow and dry ice.
In the opinion of the Bendix experts there was nothing in the theory that the radar on the DC10, if set in the `weather` mode would have detected the presence of the ice-covered slopes of the mountain ahead.