Higher blood sugar after COVID-19 infection: Should I worry?

My son has had type 2 diabetes for about two years now he is on metformin. He takes it twice a day. We have completely changed his diet and get him to exercise as much as possible. It is winter now so we go to the gym and he has a trainer.

About three weeks ago we all got sick with covid. I tested positive. My son's glucose went up to 200 while he was sick. We are well over the virus now but his numbers are going from 160 to 180 and today it was 191. I had a doctor's appointment last week for myself so I asked his doctor about the increase and he said that the virus would raise his levels. Good thing we are vaccinated.

His glucose is normally between 120 and 130. The last time his A1C was checked it was 6.4 it went up a little it was 6.2. He is still coughing but seems to be over the virus. Should we wary or just wait???

Thanks