This sounds sort of similar to ds (now 12) ten years ago. The things he was afraid of fell pretty neatly into four categories: loud noises (thunder, fireworks, movies in a theater, etc.), motion (rapid motion of night-sky projection during a planetarium show, riding in a boat in calm water), certain physical sensations (bare feet on grass, falling down in snow, having his ears examined by a doctor), and people in some sort of disguise (Chuck E. Cheese, mall Santas).
(I later heard about sense-seeking and sense-avoiding kids, and decided ds was probably among the latter, albeit not an extreme case.)
Our first reaction was to stop exposing him to the things that upset him the most, since he was unreachable by reason during the worst episodes. Then over a period of years we gradually exposed him to mild, then stronger versions of each trigger. By the time he was 6 his fears were on the wane; to be on the safe side his pediatrician recommended he be evaluated by a psychiatrist for possible anxiety disorder, but her verdict was, 'He's perfectly normal'.
YMMV of course, but it's possible that with (or even without) slow acclimation to the things that scare him, he may gradually grow out of it.
