Dog Possessing Owner

Is there anyone here who really knows how to retrain my retriever from being possessive of his pack leader owner? I live with my son who has a Golden Retriever that owns him (dog owns my son), that is follows him everywhere in the house. We also have a Boston Terrier who is not the dominate dog, he is not allowed near my son, Duke does not bit, he will sit on Boss or push him away with his bigger body. I told my 23 year old son its not right Duke should not get his way all the time. When we play ball in the yard, Duke grabs the ball from Boss the Boston Terrier then tries to keep the ball for himself. Boss wants to bring it to one of us but Duke takes it away from him. I think this is reinforcing Duke's dominating behavior letting him grab this ball all the time from Boss. Then if Boss gets the ball and brings it to us, Duke sits on him which makes Boss drop the ball and Duke grabs the ball. My son thinks its funny, I think its all wrong. When son goes to work Duke awaits for his return the whole day at the living room door where he went out. Duke adores my son for letting him be ruled by him, thats my feeling. Cesar Millan on tv says dogs know only two things, dominance and submissiveness. Around my son this behavior is dominance and possessing my son.