Hi
@pattendown
So sorry to have to meet you here but this forum is the best place to be for friendly, knowledgable advice.
I'm sorry your OH is burying his head in the sand. I can understand how you must be feeling like banging your head against a brick wall.
You say his mum and brother have Type 1 so yes, as Freema says, Type 1s are able to calculate insulin to cover the carbs they eat. However, Type 2 is very much a different condition. There is an element of 'Insulin Resistance' which means that, although you produce the insulin (whereas Type 1's don't) your body doesn't utilise the insulin properly so glucose levels rise. Although Metformin enables the cells to utilise the insulin better, there is still an issue and it's the raised glucose levels in your system that gradually (or sooner) cause problems, mainly to the nerves and/or circulation, hence many diabetic complications involve losing toes/feet/legs, heart issues and more.
The best way to deal with Type 2 and to minimise complications, is to control your glucose levels. The best way to do this is to control the carbs you eat. If you haven't already, I seriously recommend you buy yourself a Glucometer (SD codefree is reasonable price/function and has the cheapest test strips). In spite of the 'professionals' telling you that Type 2's don't need to test, and to eat carbs, by testing you can work out which foods you can/cannot tolerate and at what level your Glucose levels are. Without this, it's basically impossible to expect anyone to control your Glucose levels. This will take time to get used to.
I suggest, when you get a glucometer and start testing (immediately before your first bite, and then again at 2 hours) you show your OH the effect of your meal. Gradually, he will, hopefully, learn more about Type 2 and realise how it is controllable by checking the carbs etc. Share all the information you find, especially Daisy1's post, so that he will soon be on 'your side'
Take it one day at a time. There is a lot to learn and it is likely to be overwhelming at first. You've got friends here, so do ask, and let us know how you are doing