Drowning your sorrows?? , I have the most disfunctional family ever! I would plan your son's 21st birthday at YOUR convenience and stick with it. If they do not show up it is THEIR loss!! Make is special so that he does not even notice who is missing. I have had to do this with my X-husband because his parents were divorced if one showed up the other wouldn't, (even at our wedding) so I thought "SCREW THIS" I planned an event, everyone was invitied and it was their choice to show up or not. I feel it was their loss, not mine. I hate family issues and drama!!