In the year 2000 my mother was baptised a JW. I know for myself, before I was baptised, I wrote letters apologizing for past behaviour and did like a confession thing to have a clean conscience before God. I suppose not everyone does this.
This sounds like a step in the 12 step recovery program, thats a good thing. I dont remember the Jw's teaching that.
What I think about this is: anyone who is religious in a biblical sense ultimately is a hypocryte. No one can practice what they preach. If you dont want to be a hypocyte dont preach. But that is something that humans do to fill their time on this pleasure planet. So your mothers hobby is preaching and that upsets you. That is understandable. If your an adult at the end of your fourth decade on this planet and you want peace you probably have to just let your mother do her thing and not think about it. Maybe you have to disengae or get away from your mother. You cant change her and what she does bothers you. Its understandable that what she does bothers you, but you cant do anything about it. So your options for peace or serenity are accept it, change it, or flee.
Once a child is over 18 parenting is finished by many people. I dont know if thats right or wrong but it is what I have observed. Many people dont even get 18 years worth of parenting. Your mother is the way she is. She is an adult apparently at leat 60 years old. You cant control her.
When your mother tells your brother he has to get right with God. You could translate that to. "Your an adult you have a problem, deal with it. I'm living my life, now doing my thing. I'm 60+ years old and if I like knocking on doors disturbing the neighbors that's my business." Maybe shes also saying I dont have the answers for you. Dont rain on my parade.