Family Issues Support Group
Family issues is a huge range that go from minor conflict to major misbehaviour and even abuse on the part of individual members of the family occur. Whether you feel you are in a dysfunctional family or you're dealing with a very specific issue, this is the place to talk about it and find others who might be going through the same thing.

As for boycotting family events...no, you likely won't be missed by your siblings. Family boycotts seldom work. Instead people just get used to having the events without you around. If your father is still living, he's the one that will get hurt the most from you not being there. Parents are the one group of people who never get over it.
As for being oldest...maybe it's time to put that to rest?
***My ex husband's older brother stayed with us for a number of months. He paid no bills while here either, and yes...things didn't end on a happy note. (Hint: I'm leaving the details out of the disrepectful things he said to us.) There comes a time to Let Things Go. Issues between us don't have to be resolved for either of us to attend family events. Events really should be neutral territory.***