Fallen Tree

So I'm visiting my brother in Nashville and he shows me that his car's windshield is basically shattered because while he was parked at his apartment complex, a storm caused a tree branch to fall and hit his windshield. He talked to the office and they refused to pay for it saying it is not covered by their insurance. I was wondering if that could possibly be true? How are they not responsible for their property falling and damaging someone else's property.