Darling, granny still KNOWINGLY is abusing you using the silent treatment/knowing you are about to leave, yet she is still silent. How about you leave, then see how long it takes you to WANT to call granny, out/about anything new in your life/or just talking about the weather. See she has maligned you since you were born. You know this, your mom knows this, and dad does too. See the next time dad calls his mommy, she will blast him AGAIN about how disrespectful YOU are to her. He shares that because he doesn't want his mommy to keep harping on him about disrespectful you. Guess what, those are dad's issues, granny/his inability to stick up for you against his mommy/granny not getting her abusive ways have finally been called out and NO don't apologize. Dad AND granny owe you apologies, and I am sure you are holding your breath for those to come about no? GOOD. Move and move on into YOUR adulthood.