Hi this is an interesting question. Often this kind of behaviour is carried out on themselves rather than another cat. Often over grooming is caused by anxiety and stress. The only thing i can think of is that your male cat is feeling a little anxious about the kitten and is over compensating with his grooming. This could also account for the whisker biting.
I would seek advice from your vet who may recommend some form of calming medication for your male cat. Other wise the only alternative is to either separate the two for a while or supervise the grooming sessions.
Cats can be funny things and can behave in very strange ways to changes to their world. I hope the problem resolves itself soon.
