Boy, your Mom sure could pick 'em..NOT..
I am so sorry as to the horrors that have happened to you, in your life..

My unsolicited advice to you is to FAGEDDABOUDIT!! Get on with your nice life with DH2B and DDs and don't look back.
Your Mom made a lot of bad choices and this is just another one. You can't change your DM or Sis, so don't mess up your mind trying.
Save yourself and just pray for DM and DS..
