There is a reason why diabetes rates are higher in low income communities, the easiest way to stretch the food budget is loading up on cheap starches. Unfortunately if you have a genetic tendency for T2 these types of foods are unhealthy.
You are doing the right thing in being patient, but don't give up, eating lots of starches is not good for you. Here's a thread from here on tuD discussing eating low carb on a budget, perhaps this will give you some ideas for things to suggest to your Mom. It's not easy but if you are creative it can be done.
I admire you for your persistence in dealing with this and feel that by educating yourself and remaining patient you will be able to resolve this.