Scott,
In most cases a "frost" will kill the leaves, but not the tree. On the other hand, a "hard freeze" will, more than likely, kill the tree. But the good news is that fig trees are a lot more resilient than most people think. I had one tree freeze, and it killed everything right down to the ground, but next season when things began to warm up, new shoots started coming up through the ground and by Summers end the tree had flushed out really nice.(reduced in size, but alive). The more I work with these fig trees the more they amaze me.
Good Luck With Your Tree,