If I had a friend like your husband that wanted to hear my opinion, I would tell him to use your BG meter and test his fasting blood sugar for a few weeks. I would also encourage him to check around a few meals, say at mealtime and 1-2 hours later. Not every meal, just a select representative few. Then let the results decide his next move.
If it were me, I would want to know as soon as possible about a glucose impairment because early action regarding diet and exercise can have the best effect.
But if your husband is resistant to talking about it or considering any line of action greater than his perceived sense of what he needs to do, then there's not much any one can do.
The last thing most people want to talk about is a change in the way they eat. This is considered even more radical than asking someone to change political party or religion. It's very personal and all wrapped up in our personal history and emotional makeup. Perhaps this is the force that has most shaped doctors' policy decision to call early diabetes, prediabetes.