How can be the 8503 condition on Australian Tourist visa be avoided?
It sounds like he has his visa under Subclass 679 (Sponsored Family Visitor Visa). The short answer is that there is virtually no chance he will be able to waive 8503. It can only be waived in ‘Exceptional Circumstances’ (emphasis added), so unless there is nothing short of a death in your family whilst he is in Australia, the condition will not be waived and I don’t encourage you to attempt to do so either as it may raise suspicions as to his true intentions for coming to Australia and hinder his chance at gaining a visa in the future. If you want further clarification I suggest you have a look at this fact sheet on the Department of Immigration website: http://www.immi.gov.