Ausprop, I don't think that your friend has to worry too much about Greece. Their total debt is ?315 billion, the EU has a GDP of ?13 trillion. Unless there are a lot of weird derivatives hitched to it, the loss could be absorbed if it was written off.
Besides, the UK is insulated to some extent by a separate currency.
The problem is that Syriza were elected on an anti-austerity platform, and seem to be finding less room for manoeuvre than they thought. On the EU side there's a worry that giving too much ground might allow the larger economies of Italy and Spain to seek debt forgiveness, and the numbers there are much bigger.