4.9 is fine; but you need to know how much active insulin he's got in him.
How did you do a blood test without waking him though?!
You certainly don't need to treat that as a hypo, but if you are worried just test again in half an hour.
That aside blood sugars tend to rise in the mornings and depending on what insulin regime you are on he probably only had background insulin in his system. So, that figure would probably not be going down. If the background insulin is too high though that might not apply.
If you get a 4.9 after eating then you need to keep an eye on it as it may indicate that the insulin to carb amounts were wrong and he's heading for a hypo.
At 14 he's within the age group for a pump I think; have you discussed that? If one of my children became a Type 1 I'd want them to be on a pump.
Depending on how supportive your diabetic team is you might be able to get them to lend you a constant glucose monitor for a week or so to get a good handle on what is happening to your son's blood sugars overnight. Possibly that is harder to do than say!
Best
Dillinger