night time blood sugers

Personally I still eat when my levels are higher than expected, but many people would advise against this.

I always do my correction dose separate to my food bolus and before I eat.

It sounds as if your son is swinging from highs to lows and this too can impact hugely on quality of life and longterm outlook.

Lows are far more of a concern than highs to me, as your son may lose his hypo awareness and need assistance.. He would to me be more likely to end up in hospital from a low than dka from what you have posted...

A snackpot is not the ideal food to eat to stave off a hypo. Far better to have 15g of quick acting food.. (7 dolly mixtures for me) and a biscuit than a snackpot.

If your son is having low levels. It would be an idea to test 2 hourly for a day or two and also at night have a test at 3am for a few nights to see what is happening during the night. Even better would be to have one night of testing at 1, 3 and 5am and another night at 2,4 and 6am.
This would give your son a better chance to even out his levels and to adjust his insulin.

Give that a go first. Then it will give an idea of levels. Then if you post the readings and times an what time last ate etc.. Hardship for a couple of nights, but it will pay off dividends...