You do not need to be sorry to have brought this topic up. You did not feel validated by the way your dad responded and I can understand the pain you would feel in this. I have had many people, Christians and non-Christians alike, who have not been able to understand and said things to me about being able to get over it and get on with other things and forget about the past, and though I know they really do care, it has been hard, and I know that for me within my journey of healing it has been so important to also allow myself to get the support from those who do understand and can support me and allow my feelings to be validated through it.
I do also agree that PTSD can be healed, but know it is about building up trust again when you have been so broken and am praying for you within it to really know that you can find this safety in God, and that He does care so much for everything you are feeling and going through, to the extent that He really is prepared to take it all fully on Himself.
I once had a true story shared with me about a group of hostages who were huddled together and totally terrified, and a group of soldiers came in to rescue them. They were all still so scared and none of them would get up and follow the soldiers, and then one of them recognising their fear, put down his gun, put down his defences, and went and joined them in the group in the huddle. From this place when they could really relate to him and see that he was really there for them and did understand, they were able to build up that trust in him and did get up and follow him to the safety and freedom they needed so much. In this I see so much of Jesus and the fact that He understands and really does come to be with us in the middle of everything we go through. He understands totally why it is a journey and process to be able to learn to trust Him and come through and bring everything to Him, but I do believe more and more that as we do this, we do find more freedom in Him, and do know that He does totally understand all of where we are coming from and why we find it so hard, and really do know that He does see so much what your heart is and that you do love Him so much and do know that you can totally find safety in Him, and that He will lead you more and more into that day by day, and that in reality the only important thing is the place we are at in Him and that we are there with Him, and that wherever we are on the journey that is all that matters, as when He leads us, He will bring us through it all.
I hope that helps you a bit and hope you do not mind me going on so much, but kind of had all those thoughts in my head as I was reading and am praying you really can know that your heavenly father does totally understand and does not see you as bad and a sinner because you are still struggling so much with these issues, but really does feel all your pain and that it really does hurt Him so much to see you going through all the things you are going through.
God Bless
Helen