So maybe as a family they could put their hands in their own pocket and buy a family vehicle that suits their needs, as we all used to do. NDIS is just like Child Care system; all existential needs through luck or choice, automatically become every one else's problem, ie,the public purse. Both are fiscally unsustainable.
Don't have kids you haven't got time to nurture. If you haven't got time cause you can afford to buy some of your life back, then maybe you are just in the wrong place. Maybe all the services in big city living are not really worth it.
Maybe "less" is more.
I do feel for your work mate; his sons' "profound needs" are competing against a flood of "spectrum dis-orders", where adversity to bright lights and noise is competing against what is an obvious physical disability fact, for any help.
