Still, I would prefer to "quotient out the money", and say either the demand is met or it isn't? To the extent it is met, perhaps there are imports of material goods or domestic labor (nurses?)

I don't think it makes sense to worry about "domestic debt" in the same way, given the non-liberal political economy. Of course that doesn't mean there aren't limits, but the limits maybe would take the form of e.g. rising discontent and decreased productivity if it feels like an old-people-focused service economy with nothing in it for the workers.