Oh boy.
Have your parents have shown some real willingness to grow and change and make efforts to apologize for past wrongs--as evidenced say, by becoming sober or doing therapy of their own and then reaching out to you with concern and humility?

If so, I would consider some sessions of family therapy with a separate therapist with the goal not being so much confrontation but openness and healing.

If not, I would really consider this a fantasy that you get to have in your therapeutic relationship but need to grieve that you will never have it in actuality with your parents. Think about how you wish you could express your hurt and anger and about the thoughtful, honest, humble, loving response you'd like to get. Write out what you wish they could say. Talk about it. Cry about it. But don't act on it. It's likely to lead to further abuse and heartbreak.