Biting help

My Flemish Giant, Chester, won't stop biting my stepdad. Some days, he won't do anything, but some days he bites pretty hard. My stepdad will be feeding the rabbits and Chester will randomly bite the side of his hand. Jesse(stepdad) pets Chester and he'll bite, then go right back to normal. He seems completely normal before and after the biting. I'm not really sure what his deal is. Once Chester got so frustrated that he bit through a glass bowl, so he doesn't bite as hard as he can when he bites people. help?

Is Chester neutered?He may see your stepdad as rivalry.I have a conti,Willow and he used to bite anyone when he was in a bad mode when he was younger.maybe you should try and put your stepdad and Chester in a neutral place with lots of treats and see if he acts any differently.