The sugar contents will vary from mead to mead, a dry mead will have less residual sugar than a sweet mead. To date, all of the meads we produce hover around the semi-sweet range. The sugars will be a little more than a grape wine but fairly similar.
Although we haven’t had our own mead tested for sugar levels, I expect the values will be similar to the one shown here. https://www.calorieking.com/au/en/foods/f/calories-in-wine-honey-mead-125-alc/3JAPRPgGR8CNtO5AxBFjNg
From what I understand diabetics are generally advised to avoid all alcohol as it affects them more than those without diabetes, so our position is you should follow whatever your doctor tells you is best for you.
If you choose to drink anyway, know that mead will have a little higher sugar levels than a typical wine. Consumer moderately and not on an empty stomach.