As MeganB recommended, I’d check out the “Honoring Ancestors when You’re Adopted” piece by Patti Wigington. I haven’t read it myself, but I’m assuming it is a great resource! I’m currently reading a book by her, Badass Ancestors: Finding Your Power with Ancestral Guides for Book Club VIII that I haven’t finished quite yet, but I’m hoping to do so in the next few days so I can post my review! Badass Ancestors is AMAZING so far, and provides a TON of information on working with your ancestors for various situations, including if you (or by logical extension, your parents) are adopted or have “problem anestors.” What I love about the book is that as compact as it is, there’s a massive amount of information in it, and where she doesn’t go into too much detail, she provides excellent prompts and suggestions/recommendations for exploring that particular topic further.
I’ll try to remember to tag you in the review when I post it so that you can see if my input on it provides any insight into whether or not you may be interested in it 