It's really hard to say what's happening without knowing what your son eats for lunch, how much he boluses for it, what time he eats and what exercise he has in the afternoon. If this was happening to me, the first thing I'd do would be to look at the carbs in my lunch and see if they need to be reduced to stop the spike. That would mean a smaller bolus and less chance of a hypo later. However, this is not advice, simply what I'd do for me, and as I've said there's a lot of information missing as to your son's activity etc, and of course people do vary in the honeymoon period. Sadly, managing T1 is sometimes more of an art than a science, though you will figure it out - and there's no such thing as perfect! I wish you and your son the very best in working out what's best for him.