Fire drills will follow him through his school career. What upsets him about them? Is the alarm sound, or the idea of the school being on fire upsetting? Seems it could be either.
This fear could turn into a phobia if it isn't addressed. I'd start by saying on fire drill day, we do _____ in the evening. Whatever it is he LOVES, do that. If he loves bowling, that's where you're going that evening. Or whatever.
That way, when that alarm goes off, it's good news.
Best wishes.
Does he still cry every single day when you drop him off? If so, how long does he cry? His teacher will know this information. Being a retired elementary school principal - these are important questions. Martial arts classes, while having a lot of worth, would take way to long to help him. You need to deal with the here and now.
Oh, do let his teacher know of these problems. It is their responsibility to protect the kids.
Hi, these are fears that he needs to work out him self as stem from a lack of confidence. The more independent you allow him to be the more he can handle fears. You can build confidence in him by maybe taking to to some martial arts classes where he can learn self defense. Im not saying this in a bad way but only from being a young boy myself once but it would appear he is being coddled at home. Being overprotective can lead to all kinds of fears.