Artificial sweeteners that don't affect blood sugar?

I'm not actually diabetic but my boyfriend is T1. He really struggles with keeping his numbers in a good range so he's been on an very low carb diet to control them. This cuts out most tasty desserts but I want to surprise him with a low carb cheesecake. I've found recipes and they all use artificial sweeteners but I don't want to hand him something and say its low carb but them have his bs spike from those sweeteners.

So do they affect blood sugar and do certain kinds have different effects? Is there any one specifically you would recommend, either based on bs or just pure taste? Also something that I saw a lot was talking about net carbs. This seemed to disregard fiber as a carb. Does fiber not raise bs? I was always under the impression that you bolus for total carb. Along those same lines, my boyfriend told me that generally nuts don't need to be corrected for. In most recipes, almond flour was used. Does that not count towards the carb content then? Coconut flour (in 1/4 cup is 16g total carb, 10g fiber, and 2g sugar) was also mentioned in many of them so does that also fall under the same umbrella as almond flour?

Here were some of the recipes I was looking at in. http://ift.tt/2frY16q http://ift.tt/2qTcv6I http://ift.tt/2umShCv

If you have any other helpful tips or recipes that are tried and true they would be much appreciated. I'm just doing what I can to support him since his numbers are often discouraging and the diet isn't exactly fun.