i missed this post and started to read through it. there's a lot here and i'm not sure what all has been covered. so just let me add my thoughts on the what you posed on the opening pages about your mom and visiting her.
first, let me say how sorry i am that your mom has lung cancer. this is so sad. second, it is typical for parents not to tell their children when they are going in for tests, only the results of the tests. it is to keep their kids from worrying until there is something to worry about. so don't feel too bad about that part of it - it's normal. i would do the same and not tell my son until i knew the answer.
as for your visit with her: you kept saying - several times - that you wondered if she would apologize to you, wanted her to apologize, knew she wouldn't apologize - and so on. what i'm hearing is that you need her to validate and recognize what she did to you. you need to hear her say it and apologize. i think that's fair and i think you deserve it. i think it will give you a sense of peace. i also think that you could be at peace WITH her if she gave you that one thing. i agree so much that you need to know that she is sorry.
i would give her the opportunity to say it, whether in a phone call or a visit, and if she doesn't, then i'd bring it up. i just tell her what you need and why. that may not be the way you want it to be, but it would be better than if you keep waiting and not getting what you need.
the inner part of you loves your mom and wants to be there for her. you just need this from her. i believe she will give it to you and make you feel better about it. but you may have to ask for it.
i feel so badly for you that you even have to wonder whether she will apologize or not. i'm sorry, sweetie.