Re: Is there such a thing as good sugar?

Yes, white stevia is further processed. You can't really use either for baking, of course the dish will be sweet but it will not have the bulk nor will it carmelize, etc. Sugar is part of a chemical reaction in baking.
You could use stuff like your cane sugar, or honey.

The sad thing is, there are rarely any "healthy alternatives." If one has a health condition, one needs CHANGE, not substitutes. Probably whatever you want to bake should not be eaten, Sugar or no. Flour is just about as bad. You probably know this. I know it's really hard to get friends and relatives to listen, or be willing to change, even when they have a serious problem. Best wishes, hope you can encourage and motivate your sister for her benefit!