The idea that government spending somehow manages to pay itself back is the complete opposite of fiscal conservatism, at least in my understanding.
But that's why people need to take a critical look at things. It's not about the short term, but the long term. Taking care of the populace is akin to investing.
Do fiscal conservatives think there is a finite amount of wealth? I'd wager that most don't. Otherwise they'd more inclined to socialism or communism, possibly clamoring to "eat the rich".
From there, one can start thinking about "how is wealth created?" and realize that social programs lead to more wealth creation in the long term. Sure, we spend money now to help that kid eat a warm meal or receive a better education, but 10 years from now he'll contribute back far more wealth than was spent. Perhaps they become a doctor, saving countless lives (each of which also contribute to "wealth" in their own way). Or perhaps they become an inventor, an engineer? Who knows, but studies have shown that social programs do, in fact, pay off.
So yes, in the immediate it isn't "fiscally conservative" according to some narrow and overly strict definition, but in the long term it is fiscally conservative. Social programs are an investment in humanity's future, and they end up paying numerous dividends in the long run. Wealth, health, community, happiness, progress. What's not to love?
Helicopter money also stimulates the economy.