((((hugs))))
I am so sorry that you've had to deal with such tragedies.

I can truly understand what you are talking about & it tears my heart out! It has got to hurt, extensively, to have such an unhealthy family life.
My family life was extremely sad & crazy as well, but I never lost anyone that I actually loved...until I was 21 years-old. My grandma. She was the glue that held our sick family together. So, in retrospect, I can see that her death is what started me seeing the "real world". That is when the real pain started kicking in for me. When I actually could see where I stood in other family member's hearts. THAT is what really freaking hurt me.
Gentle hugs to you. In my experience, I've had to quit DBT a couple of times, because I just was not ready. However, I've also recognized cues that I need to get back into it & try a few times too, LOL! So, I'm in it now, and I find myself struggling to continue (from time to time)...I just keep trying. I keep on going (like the little train) because I have to. My daughters need me. That is my motivation to continue in this world. I cannot continue my family's sick and unhealthy patterns, nor can I simply escape it, I must keep trying.
That is what I do. I also gain some pleasure in the thought of possibly helping others with their inner demons as well. It is a daily struggle, I must confess. But, I keep on going...in hope that someday, some day I will be okay.
((((hugs))))