Moving to Australia with Kiwi husband, German children.

Hi there. We currently live in Germany, but my husband may have the opportunity to work in Australia. I am Malaysian, but both my children have German passports while my husband has German and NZ passport. I am told we need to apply for Aussie PR to be able to qualify for benefits. Which form would we need to fill, and will we all get healthcare if granted PR? My oldest son has a rare genetic disorder so we'd need access to Early Intervention Services and etc. It's all a little complicated and would appreciate any advice!