Hi Sarah
I can 100% relate to how you felt about the birthday cake. My son was discharged from the hospital on the eve of his 16th birthday. Prior to him being in hospital he and I had been out food shopping specifically for his birthday do - loads of rubbish buffet food, gateaux and ice cream!! Of course the day came and I felt awful. It was all over bank holidays too so rather than a home visit, we had two phone calls a day the first few days from whichever nurse was on duty, and on the first call on his birthday I just broke down on the phone and sobbed. I said how awful it was that he couldn't have any of this food, all things he had chosen, and basically she said nonsense. She advised that he just filled his plate the once and didn't go back for more, but that he could have a piece of gateau or ice cream too if he wanted. I grant you this was only day 4 of his whole diabetes journey and we hadn't even started carb counting at that point (dietician was on holiday for a couple more days) he was just on fixed doses. His levels went all over the place, and we did make a panic phone call at around midnight that night as he was even higher than at diagnosis, but they were very laid back about it.
At the end of the day, he is always going to face situations like this. You definitely did the right thing telling him he could have cake and that it would be his pudding, I would do exactly the same thing. You could always point out that with him not having seconds yesterday there is some left for today, so he can enjoy another piece this evening as a pudding.
Out of interest, does your son have a big appetite normally, or just whilst his body is recovering? My son has a big weight issue and does eat really badly, despite knowing all the recommendations. (It's not that I serve up rubbish food all the time, but he has access to his own money and pops over our local shop all the time buying whatever he fancies on top of main meals). He is no example to follow though as his control at the moment is dire, but we were told right from the off that no food is banned, he just has to calculate and bolus for it accordingly. That's where my son falls down now as he is not injecting properly, skipping 2/3 of his injections most of the time these past few months, as well as eating cakes, sweets, chocolate etc.
Instilling good habits in your son now is so important. Do allow occasional treats. If you do think he is likely to want a second piece in future, just make sure he has extra appropriate units of insulin before his meal, or delay his injection until halfway through his meal when he knows whether or not he wants cake and how much, then calculate accordingly. He is not going to want to go through life denying himself things all the time. It just doesn't happen in the real world. The important thing is just making sure he does inject.
Hope school has gone well for him for the rest of the week. At least you have the weekend now so can relax a little bit.
Keep your chin up.
Tina x