I think there was something or other for grandparents here at one stage though that may have changed now along with everything else (I looked up Centrelink nonsense to see if the big two were eligibile for any financial assistance and I could be wrong again but as far as I could tell from the convoluted website and some other person's experience, apparently the "dependent" age is now 25?).
I think more multigenerational houses (either purpose built to begin with or "granny flats" or I think some places have got like complexes of houses on a decent sized property that a few generations of one family will live) are a good idea anyway but they take up more space than flats or single dwellings crammed into a "huge" 400sqm "family-sized" block and would probably make less money and also would create stronger family ties maybe which according to conspiracy theories governments don't want because fractured selfish stupid population is much easier to control XD