Unless you find a low carb beer (there are some) then beers are to be avoided. They are known as liquid bread. Maybe your friends have meds to help them?
No my friends do not take any meds, it's purely diet controlled. A pint of beer has about 30g of sugar but depending on the alcohol level this can be counteracted by the alcohol later after drinking it.
I drink a pint, ot two, of beer and have to check my BG later and correct any problems.