@hnvilcek Hi Heather, and welcome to the JDRF TypeOneNation Forum! I’m not here as a medical advisor so, my comments will be based on what I’ve encountered and learned during 64 years living with MY diabetes - each of us can have different results.
My first thought is to let your son be a real boy, live fully everything in life and stay active - you and he will learn how to make adjustments in the three basic elements - food, and activity, balanced with insulin. In other words, design diabetes management to fit HIS life; not always as simple as the words I wrote.
If you want his BG readings to be the same every day, send him to school 7 days a week - NO. What I can see as a possible pattern is his activity level, including nap.
Sleep is the time period when our bodies work hard to “fix” our bodies. It has been noted by people who have lived a while with diabetes and use insulin pump along with CGM for Automatic Insulin Delivery systems [AIDs] that more insulin is required during good sleep than at other times of the day - your son’s nap may be a contributor. BUT, let him nap, and then consider giving him a “little extra” insulin [Humalog] at dinner. Be careful that this correction bolus is not too much insulin.
Another thought is to compare his school activity level with his Saturday / Sunday level. Considerably higher weekend morning activity could possibly cause an afternoon BG spike. An example, if he is running hard, those tired leg muscles may be “healing” themselves during nap and causing the BG rise. As Bill @rs3880 pointed out, upon awakening his body may by producing the steroid adrenalin which almost always causes a rise in BG.
Enjoy your life with your son, and celebrate Mother’s Day.