For T2 diabetics then low-carb is the best diet. If you're properly low-carbing, the jump to Paleo is a small one anyway. I'd put the focus on low-carb rather than Paleo to start with, because Paleo is a pretty broad church these days, with many people enjoying "safe starches". Unfortunately, there is no such thing as a "safe starch" if you are a T2 diabetic (unless you eat it in very small quantities).
All carbohydrates are bad for him - not just sugar, as they all ultimately get converted to glucose in his blood.
If I was him I'd try and limit my (net) carbohydrate intake to less than 100g a day, and test my glood glucose before and two hours after every meal. The initial aim would be to keep his BG below 140 mg/dl (or 7.8 mmol/l) at the two hour mark.
I'd cut out bread, pasta, rice, potatoes, anything made from grains and anything with sugar or flour in it. He can eat lots of meat, lots of green veg, lots of eggs, and some cheese and cream.
What drugs is he on? He might need to be careful cutting back on his carbs if he is on an pancreas stimulating drug. If he's just on metformin he'll be fine, although getting used to "normal" blood glucose levels involves headaches for the first few months.
I've being doing low-carb Paleo for the last 18 months, and my HbA1c is 4.9% (which is better than most non-diabetics). I've never felt fitter, healthier or happier. If the cured my diabetes tomorrow, I'd still never go back to the carbs (apart from some "safe starches").