I use my food processed to blend cauliflower, then microwave it with a tablespoon of water for a couple of minutes, add seasoning and sometimes chilli flakes or ground garlic and use it instead of rice/pasta, works a treat
I find it spikes me as much as wholegrain rice, but less than white rice. I use LC Cauli mash as described by others, or I use a Lidl high protein roll instead. Even a slice of seeded batch loaf has less effect on me than cousccous.
Can't really give advice without knowing more about your medication - if any and type of diabetes too, but at least couscous is not as high in carbs as rice or other grains.
Do you have a meter to see how you react?
A spot of dancing always seems to lower my levels.