After our second-year anniversary, we took a break for a Summer and got back together. My boyfriend and I slowly worked out our relationship, going on dates acknowledged by both my parents and having him over for dinner. He has since become almost part of my family, even to the point of helping to cook for our Summer barbecues and fixing the home computer. Nonetheless, he still feels incredibly shy and quiet around my parents. For example, my parents would inquire about him and his school life, and he would not really ask anything about theirs or start any casual conversations with them.
At our house Christmas party, upon arrival, my boyfriend did a general "hi everyone" greeting to all of our guests in the house but did not personally greet my parents and each of our relatives and family friends since he said he did not know our guests well enough to greet them. My parents took issue as they perceived his actions to be disrespectful and unappreciative.
On the other hand, my boyfriend says that he cannot easily relate to them unlike with his friends' parents whom he can easily greet and chat with. I love him very much, and I don't want this to hinder all the love and care we give to each other after all these years, but I don't want to let down my parents and relatives with my boyfriend being perceived as bad-mannered and rude. I want to help him out as well as help out my parents with this particular issue. How do I best navigate and correct this?