Liam,
I so sympathize with your position. My father was my abuser and a pastor of our church all during my childhood. My story is on the boards. I forgave him some time ago but it was a long long time between when I left home and when I finally was able to forgive him.
Liam there is a huge differenct in forgiving someone and continuing to allow them to hurt you. There are conawquences to actions.
If some one lies to me I can forgive them even if they lie to me a hundred time. This does not mean I believe them anymore or take their word for anything ever again.
If someone rapes me, I can forgive the rape and maybe even harbor no ill feeings against them but I will still report it and file charges. There are concequences to actions and people need to understand this.
If I were in your shoes I would disclose. I would tell on my father. I must confess to you here that I didn't do that with my father. I did not know what I know now or I would have. I believed I was the only person my father had touched. I was wrong and I will live with the consequences of that for the rest of my life. But if I had it to do over again, yes I would tell anyone and everyone I could. I would have stopped him. It is rare a perp only has one victim. I know that now.
Liam there is an excellent book on forgiveness by Lewis B Smedes called "Forgive and Forget, healing the hurts we don't deserve." It is from a Christian perspective and I think would be very helpful to you in understanding what forgiveness is and what it is not.
You can forgive your father but you cannot let him rule your life with his secrets and intimidation. You can never trust him again snd should not as he has already proven he will not respect your boundaries.
If and only if he has confessed and repented and attempted to make amends I would then maintain a cautious relationship with him but I would watch him for the rest of his life.
Love him, forgive him but keep your boundaries intact and your distance. That is my opinion as a son of an abuser who wished someone had given me this talk 50 years ago. Good luck Liam and welcome to Malesurvivor.