Barb, you can't make your sister into someone she isn't. It just doesn't work. As much as you would like a close relationship with her, she just doesn't seem to be the type. You may just have to let go of those feelings. You have tried and tried. She just doesn't have it to give.
What good news about your neighbor! Take it slow. Baby steps in friendship. That was nice of her to get her brother to help and the groceries. It's a wonderful start. I can imagine how that stress is less about about that!
Keep thinking about the good. Let that fill you up. They may seem small, but more will happen.