What should I do about the harm caused by my cousins to my mother, which causes her problems when they visit?

The cousins should be taught, guided, and disciplined to stop their wrongdoings towards the mother. The mother, on the other hand, should treat them kindly and well, especially since they are orphans. She should treat them as her own children, control her emotions towards them, and remember that she is the older and wiser one. However, if her visits to them lead to problems, then it is better to avoid them, because averting harm takes precedence over gaining benefits. This should be explained to the mother gently and kindly.