Do we rise above it and be 'good people' and help our elderly parents who are vulnerable because they are our parents, or do we remember the shit they gave us growing up when we were vulnerable and some of the difficulties which arise in adulthood thereof (some of which have majorly impacted your life...) This is assuming you're still in contact with them and have been able to maintain a relationship with them
YABU - yes support them whatever
YANBU- no, they've made your life difficult so why should you help them now