First of all, I have to find someone who knows Feng Shui to show you a specific time to fill the grave. You can't blindly make up for the collapse. Generally speaking, you have to find someone who knows Feng Shui and set a specific time to fill the grave.
Secondly, the direction of borrowing soil. For the grave, we should not blindly borrow soil to fill the grave when it collapses. You still have to find a direction that understands geomantic omen, and borrow soil to fill the grave in a specific direction. Of course, this is uncertain.
In addition, there are many other taboos, and each place should be carried out according to its own traditional habits. Not every place has the same standard.
The above is my personal opinion, and I hope it will help your problem.