Dealing with a negative family member…or a person who just likes to put you down

I didn't read the whole thread but by the title and first post it does sound like my life except for that i'm the middle brother, and we basically just fell away from each other over the years, but since my mom passed away 4 months ago I've been the punching bag from both ends and am blamed for everything that has ever been wrong with this family and we are basically just not talking since. My older brother has always been designated as "in charge" of affairs ever since well before Dad died in 98. Yet somehow my younger brother and his wife who is only related by marriage have invaded and taken over everything. We've been in heated arguments like we have never been in in our lives in the past 6 months, I know they're hiding things but definitely deny that, (I get that comment from both ends even though the younger one is behind most of the bs)
Just last night I saw that my mom's house was listed for sale by Zillow, and some real estate from several states away (I had to look up the area code to see where they're out of)
I think it's some kind of sell it your self online realtor. What idiots. But they walk on water....
I drove by last night after my wife showed me the posting and there's no sign in the yard, funny since the online posting i was shown claims and open house tomorrow. Nobody has contacted me in at least 6 weeks. The paint job they did on that house is hideous (every FLAT white ugh they even painted over paneling of which my other brother said not to.
My older brother and I wanted to wait til spring, when kids were getting done with school for the year, but noooo... They're in such a hurry. And I think they are quite ridiculous with their asking price which will be great if they get it but I think they shot us in the foot with their doings.... My sister in law claims every house in a few block area of Mom's place has sold in 5 days of listing. I know that not to be true.
I do know that none of what has sold has had a completely bare open unfinished 2nd story. A big wide open room the size of the first floor that's been rafters and studs since dad had the 2nd story added ...... It was supposed to be my sister's apartment when she finished college but she died before she could finish, so there went the ambition to finish what was started there ...
As for our ages Dave is 51 Doug is 66 and I'm 57 my sister Debbie would be 67 if she were still here. She died while in college in 1979 at 22. She got something called "toxic shock syndrome".