Summary
Maybe you can try to draw a more detailed design sketch, draw a storyboard or simulate a background story and use scenarios to help explain. I'm sorry that some English words you wrote are difficult for us to see and distinguish, and your sketch is still vague. Besides, you can not limit yourself to refrigerators, and other products convenient for the elderly are also great. We also want to see a variety of things.
Here’s our design ideas,
It may be more intuitive and acceptable for the elderly to distinguish between the color depth and the number size. I think this is a good form of expression.