My Family Is Growing Further Apart

I don't know ow to deal with the situation. My parents for many years drunk. They were never obusive, we were a well off family but I can't remember evening when my parents were sober. No one ever talked about it, sometimes it broke in some argument but there was never an honest conversation until a year ago I said to both mum and dad how much it effected me and my sister. I'm 30 now and moved out from home (even country) 8 years ago. Last year my father put up a house on sale as he has been struggling with keeping mortgage repayments for years. While the house was on a market, my sister and her husband was buying a house and agreement was that my father will buy their flat of them so they can pay the mortgage off. There is a quite complicated situation with my sisters mortgages and in the end if my father bought her flat, that's will still be a mortgage on it. So my dad after thinking about it changed his mind a bought a little house for cash. He said he didn't want a flat, he doeasmt want to live in a property that has got mortgage on it, as the mortgage would have been still my sister and if anything should happen to her, he would not be able to keep repayments. Since then my sister is horrible to my patents. She doesn't let them see her doughtet, their only grandchild. She speaks to them with no respect, so is her husband and she is clear that she hates them. I tried to understand her, that she has been hurt because of their drinking( now they barely drink) that my dad promised her to buy a flat of her and backed out (that led to her financial struggles to certain extend), and I can understand why she is angry, but I can't understand that nothing can convince her to at least try to solve the situation. She is so rude and out of order, that one day after speaking to my dad I e-mailed her and told her that I don't want to talk to her until she starts behaving. Maybe not a smartest move I've made, but I was just do angry and she wouldn't talk to me about this on the phone. That wad 3 weeks ago and I haven't heard from her. My dad is not the smartest guy in a word, he does and say a lot of things without thinking about consequences, he is one of those annoying people that do everything in a rush and their stress is contagious, but he is a good person. When he was well off me and my sister had everything. No he has got nothing and he only wants his daughter and granddaughter back. How to speak to my sister and ask to stop being so coldhearted?
Pa55w0rd Pa55w0rd
26-30
May 4, 2012