HI,
Type-1s cannot manage with a long-acting insulin alone, if you're son's diabetes nurse had any education in diabetes management, she should at least know that, it's basic knowledge. The numbers you have given when he was taking when taking the Humalog were good, apart form the 2.9 at lunch. Had he done any physical excercise after breakfast?
You haven't mentioned what you're son had for his meals, if these were carb-based that would cause a rise in BG and perhaps explain the further increase throughout the day. Another theory is that Lantus, although marketed as a 24 hour basal insulin, does not always work that way for many people. In such cases it can make it virtually impossible to find a pattern/explanation to what is happening re-BG levels.
The results your son is having without Humalog are too high after meals, so leaving out just the breakfast humalog may solve the lunch hypo. It sounds like you and your son are doing everything you can to try to control things, so don't beat yourself up, it doesn't sound like you're doing anything wrong. Your son's diabetes nurse is probably being extra cautious as he's on very small doses. She might also be watching for the "honeymoon period" which occurs after diagnosis, when the pancreas relaeases it's last stores of insulin again for a short period of time, usually a couple of weeks. During this "honeymoon period", the patient may need no insulin at all. This can occur many months after diagnosis, mine happened 9 months after diagnosis and I was on no insulin at all; thought I was cured LOL That was 21 yrs ago.
It would help if we had more info about your son's diet, particularly carbohydrate amounts and activity. The effects of physical exercise can keep BG levels down for a few hour after.
It takes time to adjust, and occasional high BGs at this point will are unlikely to cause your son any permanent harm. It's best to put them down to experience and not dwell on it too much, although the ups and downs will make him feel a bit lousy, hopefully on the correct insulin and dosage that will resolve to some extent. Unfortunately type-1 diabetes is always a balancing act, we just get better at it over time.
Jus