I doubt kerosese would work even if he was doing it, and I certainly wouldn't put WD40 on them.
You should research using ivermectin for leg mites. Some forms can be added to their water. It's not an ideal treatment but it might actually work, in time.
You should research using ivermectin for leg mites. Some forms can be added to their water. It's not an ideal treatment but it might actually work, in time.