Welcome to SR! Welcome to this band of recovering misfits.
Everything you have read above is true, particularly:
1) Your childhood was abnormal. ACOA behaviors cross all class and ethnic boundaries.
2) You childhood is still affecting your present. You learned all about love, relationships, and responsibility from alcoholics, and those lessons do not work well in the normal world.
3) The lessons you learned as a child can be unlearned. The lessons are deeply embedded, almost at the level of instinct, and take effort to work out.
4) Only your mother can decide if she wants to recover. The unalienable dignity of any human requires us to let an addicted person direct their own life and recovery, and the experience of many families proves that helping often enables the addiction. Many ACOA's fall into addiction, but the recovery process is the same as for all addicts.
5) Your recovery is your priority, not someone else's recovery. The problem with being a martyr is that they are only useful after they die.
6) Good ideas: counseling, alanon/acoa meetings, posting here more.
I hope the visit goes well for you and your brothers.