Hello and welcome Tom,
For those of us abused by siblings, there may be shame and feeling that we are not in control. Siblings and parents are supposed to creating healthy nurturing relationships that encouraged self affirmation, working well as a team, and promoting an assertive self image. Physical and sexual abuse "freezes" those personality traits. They are not destroyed, just stopped from developing until we "thaw" them out through recovery.
Control is the desire to be able to think feel and act with assertiveness. We can begin, continue and finish a process with success. Abuse takes that healthy image away from us. We feel dependent on others to make decisions for us, and then we feel as if they are trying to control us. Some do try.
Learning what we need to truly be in control of us is a matter of recovery. Whatever brings us into recovery is a matter that keeps is continuing in recovery, but the victory of recovery is addressing all the areas the abuse froze and warped, and healing from as many of those as we are able to in our lifetime. It is a marathon, with checkpoints and timing, not a horse race.
Please, see yourself in the good and assertive way you want to, and then pursue that goal to victory, you will, I know it.