My child does not have Type 1, but I myself do, for several decades now.
I think the utmost priority here is to try to avoid or minimise hypos.
Avoidance of high blood sugars and trying for optimal blood sugars definitely need to take a back seat.
In your position I would give nova rapid only AFTER he has eaten (when he does eat). That way you can see how much has actually been eaten, and give an appropriate amount of insulin.
You will get a bit of a blood sugar spike after the meal as ideally the insulin should have been pre-meal, but the alternative is getting into a situation where insulin has been given and then food is not eaten - or only a little bit is eaten. That is way too risky, health-wise, as you will end up with bad hypos.
If he doesn't eat at all, then no nova rapid. If the slow acting insulin dosage is right then his blood sugars should remain more or less stable like this.
Oh, and a hug from me.
The whole insulin/carbohydrate/blood sugar business is tough. The learning curve at the beginning is very steep, so things do get a bit easier later on, but there will always be random things throwing a spanner in the works.