Father likely about to be diagnose with Type 2 Diabetes. I know nothing about it- what can I do?

Father is 60 and very overweight. Just got diagnosed with Type 2 diabetes, and he's going into the doctor to get more information next week. He lives in the UK.

From my understanding, this is manageable, but he has to lose weight and eat more healthy. I want to support him and help him make a plan.

Any advice or input greatly appreciated- this is all brand new to me.