Hello Flowergirl: I see this is your first post here on PC. So... welcome to Psych Central.
I know you also posted this in the Survivors of Abuse forum & received several replies. But I thought I would leave my reply here.
You asked what you should do with regard to this most difficult situation you're in. As you wrote, logically, it would make sense to simply "go no-contact" as it is typically phrased. But this would mean you would no longer see your younger brother whom you love. So you're wondering if there is a way to make your family better or what. And I'm sorry to tell you my personal opinion at least is there is not.
You can only change yourself (in my opinion.) Your parents have had many years to become the people they are. (As have your older brothers.) Imagining there might be some way you can make this all better, to my way of thinking, is simply a way of avoiding the harsh reality of your circumstances... sad as that may be.
That written, there may perhaps be things you can do to improve how you interact with your toxic family members. Here are links to a selection of 15 articles (the most I think I've ever linked anyone to), from Psych Central's archives, that (hopefully) may be of help with putting your situation into perspective & figuring out what to do about it:
You Can Only Change Yourself
You Have Permission to Cut Off Your Abuser
Stop Trying to Change People Who Don't Want to Change | Happily Imperfect
Rescuing, Resenting, and Regretting: A Codependent Pattern | Happily Imperfect
Dealing with Difficult Family Members: Don't Justify, Argue, Defend, or Explain | Happily Imperfect
https://blogs.psychcentral.com/imper...dium=popular17
https://psychcentral.com/blog/how-to...amily-members/
https://blogs.psychcentral.com/imper...toxic-parents/
https://blogs.psychcentral.com/commo...-brief-how-to/
https://psychcentral.com/lib/what-ar...do-i-get-some/
https://psychcentral.com/lib/10-way-...er-boundaries/
https://blogs.psychcentral.com/imper...hy-boundaries/
https://psychcentral.com/blog/5-ways...ficult-people/
https://psychcentral.com/blog/when-p...ur-boundaries/
https://blogs.psychcentral.com/imper...ur-boundaries/
I hope you find PC to be of benefit.
