Investing with a retired couple (parents)

Hi guys a rather complicated question coming, strap in

My parents are at the age where they are have both retired but perhaps with less that they expected to have at this point in their lives. My wife and I have a large amount of extra cash at the end of each month and would like to do something to help them out. 

Let me try to paint a picture:

They have a own outright a property in outer Melbourne  (~500K) and stocks (~250K) (that I'd describe as volatile). They are from a generation where super was not always saved and they had to withdraw what was saved before they retired to make ends meet, and look after us kids years ago. So in simple terms they are selling the stocks piece at a time to provide for themselves. They are not elligable for government assistance (or very little I understand) due to their assets, the house and stocks, so their liquid situation is not great. 

My wife and I are in a good position, we have are both employed, have a mortgage and have a fair chunk of money left each month to do with as we wish (~4K) so we have been contemplating what to do to help them out, we could just give them cash each month (as we have been doing) but that may not be sustainable if our circumstances change, kids etc. Ideas have been kicked around like purchasing a property that they could rent and there by receive government assistance, but their assets from the sale of their property would still make them inelligable (I persume). Or possibly purchasing their property and charging them very low rent, so they have an outgoing and we'd have a negative geared property. And anything in between.

This being the creative investment section I thought I might throw the doors open to how we could invest with/to assist a retired couple. I know that seems against the grain of many investments, they need cash now but investing is generally a longer term game, however if there were some way that I could invest with them somehow to remove the burden of their assets such that they could gain government assistance and extend the life of their assets longer.

After writing all that I'm not sure exactly what I'm asking but hopefully you get the idea, folks with not enough assets to provide for their future but enough to stop a pension income, how can I help?

Thanks in advance, 

Mik.