Looks like behind the scenes they may be getting their banks to fund Greece and, by extension, any other national govt. this which will buy time, though longer term it depreciates the currency, which they may want to happen as well.
As long as the banks can carry their eurozone bonds at par and book the interest as earnings and fund themselves based on implied govt guarantees there is no operational limit to how long they can continue.
The limits would be the extent to which the banking laws restrict this practice, and the political tolerance for any inflation that may get imported through the fx window should the euro continue to fall.
The other problem is the downward pressure on aggregate demand of the prerequisite ‘fiscal consolidation’ is likely to result in increased social unrest as living conditions further deteriorate.
And this could be accelerated if the fiscal consolidation were to include reductions of transfer payments.