Hi cazuk . . .
A blood-sugar level of 5 - 6 is in the non-Diabetic range, and if your husband is able to maintain blood-sugars mostly in this range he will be able to avoid all the nasty long-term complications of Diabetes.
A level of 8 is NOT in the non-Diabetic range, and if your husband maintains blood-sugars at 8+ to be "safe" he will be in danger (over the very LONG-term) of developing Diabetic complications.
I know this from experience. For many years I had blood-sugar levels in the "acceptable" range, but after 10 years of T1 Diabetes I started to develop Neuropathy (nerve damage in the eyes) anyway. I now ignore everything Doctors and Nurses say, and try to keep my blood-sugar levels in the non-Diabetic range, as human evolution intended. Best decision I ever made.
It's not a simple choice; going for levels in the non-Diabetic range means (especially during your learning phase) that you are more susceptable to Hypos. Everybody must make their own choice what is an acceptable short-term or long-term risk. Personally I find the idea of going blind and getting my feet amputated another 10 years from now absolutely terrifying. I would rather treat my Diabetes intensively and go for Gold (non-Diabetic levels and no Hypos). It's difficult, there's a lot of learning to do, but not impossible. Everybody has different genes, environmental factors, lifestyle, and preferences. So the exact method of keeping blood-sugar levels under good control will be different for each individual that tries it. Your husband now has a blood-sugar monitor that he can use to see exactly what foods and activities raise HIS levels. This monitor is THE tool to learn from. (For example, if your husband's monitor tells him that his levels at bedtime are 5 - 6 and if his levels throughout the night and in the morning are the same or higher, then any standard advice to go for pre-bed levels of 8+ seems rather foolish). Be guided by your real-life experience; not by theoretical advice from a nurse that doesn't have T1 Diabetes.
My apologies for being totally off-topic. I won't offer any answer to your original question. Just wanted to give you a hint that there is a totally different way to go than your Diabetic nurse is recommending. Many people (see the Low-Carb forum especially) come to that conclusion after years of ****** advice from medical professionals. I give you an early heads up.
I'd highly recommend "Dr Bernstein's Diabetes Solution" if you don't know it already. The author is a T1 Diabetic who became a Doctor because he was (literally) sick of all the rubbish advice that he received from the experts.
My very best wishes for you and your husband,
Antony