I feel your father will always twist anything with you , I usually see people act that way when they do not want to take responsibility for there actions past AND present.

Myself, personally I would send the letter and be prepared for it not to go well, but at least you will have truly gotten it out there.

You deserve support whether it been friends or family . You deserve better and if he can't see it or accept that you went though such a hard childhood then maybe cutting him out or greatly reducing the amount of your life you allow him to be in might be your best thing for you

(((((hugs))))))