Doesn't your mother have to watch her cholesterol? Diabetes is complicated and I don't really know much about it. Does your mother have to watch the amount of starch and simple carbs or things that turn into sugars?
One of my favorite breakfasts is left-over grits; takes too much time to make grits in the morning, at least real grits. I make mine with some low fat milk, and no cheese. I have to limit my cholesterol, though I am not diabetic. Whole wheat toast is always good. Spread something healthy on it. Avocado, nut butters, whatever is not bad for her. I like a little ricotta and fresh slices of tomato on toast.
Potatoes are a pretty classic breakfast, and can be good lots of ways: home fries, potato pancakes, etc. Ever have red flannel hash? Made with beets--very healthy! No need for pork in that. As for fiber, sweet potatoes (especially the orangey red ones labeled "yams" are king! I could easily eat a hot sweet potato with nothing more that a touch of butter and a few grains of salt. Personally I'm not big on meat for breakfast, nor do I eat eggs for breakfast, and like others have suggested, breakfast is just another meal, limited only by health restrictions and imagination. It might be useful for the original poster to list the other big no-no's, so readers can feel challenged without wasting time or contributing to a well meaning but growing pile of misinformation. Good luck!
I just read the two posts upthread and now I am totally confused.