How long has he had his nuts off?
Experience tells me that it sometimes takes a while for cats to adapt, wouldnt anyone!!!! Thank god men do not have theirs cut off....
Theres always a pecking order, it should settle down or he will learn to keep away and run like hell. He has lost his hormone induced natural feelings to be assertive and want to fight..Although it dont look like it now , he is better off. Im sure he
will get used to being a cat minus his nuts...