They sound pretty good to me. Really hard for readings to be too low unless you're on glucose lowering medication. A non diabetic might go down to 65 or 70 mg/dL at times (mid to high 3s in mmol/L) whereas a T1 like me, who injects insulin, would take sugar if I got that low, because it's possible for my injected insulin to make me go too low.
Blood Glucose Testing FAQs - Common Questions (diabetes.co.uk)
What numbers should I be aiming for with my blood sugar numbers?
The ultimate aim is to achieve numbers as close to non-diabetic values as possible, this being
between 4 and 6 mmol/L before meals and
below 8 mmol/L after meals
Those are the UK recommendations, multiply by 18 to get figures you understand. (ie 72- 108 before meals, 148 2 hours after)
Has he been officially diagnosed yet?