With regards to general du'a (not performing qadha salat), no. Praying or not praying for the well-being of the deceased is optional.
However, it is good to pray for the deceased - both for them, and also for yourself, if there are areas of conflict that need forgiveness. Sometimes it is easier to make peace with people and forgive them once they are gone.
If your parents have harmed you, it may be helpful to remember that, after they are deceased, they are no longer able to harm you. Also, most people act angrily, violently, etc, due to hormones, greed for material things, the way the body interacts with emotions, and so on, and deceased souls no longer have these things. So the deceased may also regret how they acted in this life once they are no longer affected by having a physical body. God knows best.