Ltlys

Ok, I have a situation going on here that I can't figure out for the life of me. Any of you that have read my story know that my (R)/ AB's sister (was) one of my friends. We were friends several years prior to me dating her brother.
During the course of he and I's relationship she was very much aware of her brothers heavy drinking. I vented to her many times. She saw, with her own eyes, many drunken episodes with him. She did not however, ever witness any of the really really bad episodes that happened behind closed doors. She did not see or hear any of the awful things that happened. She knew only what I had told her about those times or, anything that her brother may have told her about those especially tragic times.
Honestly, I never really trusted her 100%. Before dating her brother, I knew better than to tell her anything really personal or anything I didn't want others to know because she has a bit of a reputation for gossiping. Once I started dating him though, she and I became much closer. She often came to our house and visited.
Many times I would talk to her about my concern for him. She herself was angry with him several times for not showing up to work from being hungover. (She was his basically his boss) She would always say things to me like, "that just doesn't sound like my brother, its just the alcohol talking." She also saw him not be very short tempered with my youngest daughter and said that bothered her.
When I decided to give him the ultimatum, she was on board. She helped me set things up. She seemed quite supportive. Once he was gone however, things started to change...She chewed me out for telling someone what had happened. She was the one that got to go visit and go to counseling with him. Every time she came back from a day with him she would immediately come over and tell me how great he was and how wonderful he was. She told me of a counseling session that apparently didn't end well because I was brought up. She told me to just let him be and not interfere with this. I was so upset. She made me feel even worse. I'm not positive but, I believe there was some lies and deceit all mixed in there.
Okay so, now she comes over all the time and bothers me. Talking about her brother and such. Never asking if doing okay. If I need anything. Ignoring the fact that my kids are sad and upset. She literally acts as if nothing happened. Twice now she has showed up drunk and even joking about having to take her to rehab. One of the nights she showed up drunk she was telling me how she just didn't wanna go home. That she thought the "spark" between her and her husband was gone and that she was seeking any male attention she could find. I was just floored that she was telling me this. She mentioned that she had talked about it to her brother!?! wtf! really? its constant and Im completely confused with her behavior. Just today she sent me a text asking about getting an appointment, (I am a cosmetologist). She wanted her eyebrows waxed and proceeded to say she would have a few drinks before she came so it didn't hurt so bad!!!
Can anyone lend me any insight to this behavior? Is she just checking up on me and relaying stuff to him? Why does drinking seem to be a big joke to her? I would never do that to anyone I called my friend that was in my situation, EVER! What exactly are her motives? This is not a joke to me! This pretending that I was never in a relationship with her brother is mind blowing. Its as if she thinks he is cured now because he agreed to go to treatment. That what we went through and are currently going through is no big deal.
Any thoughts? I could sure use a little insight on this! Thanks!