I know, she was probably killed by a rock from the sky, or at least an icecream. He still has nightmares, I'm sure...
ah - wisdom! all is now clear - his mommy was killed by a frozen chunk of blue-and-brown material that fell from the sky from a passing airliner, he mistook it for an edible confection (much to his nigh-immediate dismay), and ever since that time he has had a pathological phobia about things falling from the sky... and ice cream.