Completely agree Kristingle. One of our very close family members, who understood adoption apparently, totally let us down with their behaviour and reaction to DD coming home. 3 years later and I am pretty much NC.
Based on that experience, I would absolutely agree with deciding what boundaries you want in place prior to your DC coming home, with regard to introducing your family to the DC, and stick to them.
However I have made the most amazing friends through DD - the kind that stick with you whatever you're going through!