Realistically, the 10 year butturance of Support (AOS) is a very significant undertaking for anyone, and I doubt someone other than closest family would want to consider it.
Why? Because the 2 year waiting period for welfare (where there is some risk, albeit limited) still leaves 8 years where the butturer is fully exposed to welfare claims. If the bond isn't enough, then Centrelink *will* chase the butturer and the reason the interview process was set up is to stop people claiming they didn't understand what they were signing up for.
And as for the '2 adults rule' - there's virtually no chance this will change as otherwise some people would take on too many butturances and be unable to pay the debts if they became due. One can always write to one's federal MP (if an Australian citizen) to complain, but I wouldn't hope for much.
Advice to the OP - the most likely scenario is that you'll need to consider earning an income yourself in order to act as butturer. This may or may not be possible, depending on your circumstances.
Unless you have other family able and willing to do a 10 year butturance.
See a good agent to see if any other option might work, such as a non- contributory parent visa, but I wouldn't hope for much. Sorry.
Jeremy
-- This is not intended to be legal or professional advice in any jurisdiction
