Each child gets their own NDIS plan, built around their individual needs and goals because every person is different, even within the same family.
That means most supports are funded separately for each child. Occasionally, where it genuinely makes sense, the NDIS may coordinate supports across plans but the starting point is always individual funding for each child.
One child's plan doesn't reduce another's. Each application and plan stands on its own merits.
Managing multiple plans is exactly where plan management earns its keep with one place to track every budget. Email hello@providerchoice.com.au if you'd like plan management support.