goldengirl you can say no to him without feeling guilty. If anything think of this situation as a gift to him and a gift to you. A gift to him because he gets to be an adult and take care of himself. A gift to you because you get to maintain the boundaries you set and continue to work on yourself.
Trying to make me feel sorry for him or guilty continues to be one of my xah's favorite pass times. Life is all about him. The world ought to revolve around him. Me, I'd make sure I gravitated away from that orbit so I could enjoy the holidays without the drama and guilt. Do something for YOU. He can take care of himself.