I don't blame your cousin for not wanting to stick her hand in a cat fight!! Bad idea!!
You can't watch them all the time and if the fights are that aggressive she might consider medication just to calm the situation down. I really didn't want to use meds either until Magoo and now I would swear by them!! Whatever it takes for a happy and peaceful household. The cats can't be relaxed when there is all this stress. Just enough meds to calm them not knock them out. Magoo does great and he plays all the time but now he doesn't have to freak out with every sound or activity. He is much happier and that makes ALL of us happier!!
I just take a 1/4 of a pill and roll it in a treat twice a day and that is all there is to that!!