Yin house refers to the grave of the deceased. Feng Shui usually thinks that a good Yin house should meet certain standards, such as sitting north facing south, with the left high and the right low. But these standards are not absolute, because everyone's family situation is different and needs to be adjusted and improved according to the actual situation.
Therefore, if you are worried that your uncle has found someone to look at the ancestral grave, you can consider discussing it with your family to see if you can improve your family fortune by adjusting the layout of the house or other means. At the same time, you can also consult a professional Feng Shui master or Feng Shui scholar to get more accurate advice.