I have done this myself a couple of times, I can deal with it with myself worry wise but understand how it must be a nightmare for you , as it would freak me out if it was one of mine, so my sympathies are heart felt for you.
Try not to worry too much as it sounds like you have everything covered ,so I'm sure he will be fine in a few hours time, depending on which insulin he is on it does have a "window of active time" so you could maybe keep him up a bit later than usual to keep checking but if this is not possible...as I know it's school tomorrow ,do as you suggest ,test him into the early hours.
Having said that his correction dose ratio is the same as mine and if I had eaten what you have listed I would be well covered and not go low at all, so I'm sure your son, hopefully will be fine on what he has eaten.
If you check every hour and it is trending down ,give him a small snack , if it goes up I would not correct, just write tonight off and start tomorrow as another day.
hopefully he will be fine, I'm sure he will. Let us know how you go on.