Sometimes, you got to accept that your parents won't be helpful and keep the distance from them....just be respectful and friendly...
I suggest to tell her that she got to stop complaining about your dad to you....for god sake, he's your dad and whatever he is, you love him...so she got to understand that...probably, she's still in love with your dad....she should see a therapist for sure....tell her...
In term of your loneliness...tell me something new...all of us are lonely...all of us are battling with our life for finding a job, place to live, partner and so on...you are not alone then
I'm dying to talk to my mom and tell her about my problems, but I stop myself, because based on my experience, I won't gain anything except she makes me miserable by constantly getting worry about me or getting angry at me later on and bring up my issues back to my face....now, I'm getting smarter and I just don't tell her....
here in PC is a good place if you write your problems, we will write back to you....
I recommend you to go for a hobby for yourself then you will meet like minded people and you will make quality friends that you can rely on and talk about your issues....

with love
marjan