Hi, and welcome to TypeOneNation!
100% on calling the endo for medical advice, of course.
As for how we can help, offering emotional support and information about our own experiences, I’m just not sure what you mean in your question. If his beta cells are producing insulin, but unreliably (which is the hallmark of the honeymoon stage), then unfortunately you just can’t really be sure whether he’ll need an injection for any given meal or not.
If he needs the injected-insulin assist and doesn’t get it, you’ll know afterwards when his BG goes high. A “crash” is how people usually talk about a low, which would happen if you gave him insulin and his body decided to make some, too.
Your best bet for this (very stressful, I’m sorry!) phase is to follow your endo’s prescription, and check in with the CDE (Certified Diabetes Educator), who is usually easier to reach and faster to respond than the endo, for advice on adjustments.
But as I said, I’m not sure I understood the question, so if I just missed the boat entirely, please let me know and I’ll try again.