Basal (slow acting) insulin generally SHOULD be administered at the same times and same doses each day. For someone with no natural insulin production, their basal insulin needs should not change day-to-day.
Bolus (fast acting) insulin generally SHOULD be administered to correct for high blood sugar and/or to correct for carbohydrate consumption. The amount of insulin needed should be determined by the person's insulin-to-carb ratio which varies from person-to-person.
With that said, some of this gets thrown out the door when we're talking about someone who is recently diagnosed. If your son is still in the "Honeymoon phase" meaning his pancreas still produces some insulin that can significantly affect his basal and bolus insulin requirements.
Either way, giving him fast acting insulin without eating and without intending to correct for hyperglycemia (high blood sugar) is NOT something you should do. Bolus insulin isn't meant to be taken at specific times of the day and is meant to correct for events that would otherwise cause hyperglycemia.
Disclaimer: this is something you really need to discuss with your son's doctor. It's very dangerous to implement some of this stuff without knowing what you're doing.
