I am sorry to read about your son's crumpet spikes because crumpets are yummy.
If his levels rise and fall again, all is not lost - it is probably that the carbs in the crumpets is working faster than his insulin. So you could inject earlier so the insulin peak matches the carb peak. Or you may be able to slow the carb peak by adding fat - I enjoy my crumpets with a slice of cheese on top.
A couple of other thoughts
- if your son's levels do not spike but stay high, you could increase his insulin dose
- when does he eat his crumpets? I ask because, if he has them for breakfast, this could be a Dawn Phenomenon thing rather than a crumpet thing.
- what does he put on his crumpets? As I mentioned, I have cheese. Many enjoy butter (it's as if the holes are made to drip butter through) and others enjoy jam and crumpets. If your son is a jam-boy, the jam may be the problem and a savoury topper may be easier on his diabetes.
My recent crumpet fad is due to finding a sourdough crumpet recipe - I enjoy sourdough bread but my sourdough starter was growing faster than my ability to eat the bread and the crumpets provide an alternative. By baking them myself, I have a more control over the recipe. I realise a lot of shop bought bread includes sugar which will speed up the carb absorption. I rarely add sugar to my bread.
I hope your son finds a way to continue his crumpets. Diabetes can be a pain at the best of times and taking away our comfort food is not good.