Metformin is not known to cause hypos apart from it may exacerbate low blood sugar in cases where there is not enough intake i.e. If he started dieting hard for long periods or not eating at all.
The DN may also check your feet pulses with a ultrasound type device, so make sure you washed them , you may also need to tell DVLA of your diagnosis and your treatment but other Type 1s will be able to tell you more about this..
You will also probably be referred to eye clinic to check for...
Not so sure about that artificial sweeteners have been shown to increase insulin levels, as you may known Type 2 diabetes already have too much insulin. So they may not raise bg levels but they do promote weight gain and worsen diabetes
Join the Royal Holloway study into the Diabetes Forum
https://www.diabetes.co.uk/forum/index.php?threads/Join-the-Royal-Holloway-study-into-the-Diabetes-Forum.tpann_6/
As you enter any of post threads, there are pinned posts from admin, No1 is called Notice, No.2 is called We want your feedback , No.3 is called Royal Holloway study ..it's no.3 that's no longer available
I was lucky to find a book of his called ' The Obesity Code' in local Tesco charity book stall, paid a £1 for a book that hardly looked read at all, cover price new £14.99.
It's an excellent book..!