Darth, I'm sorry for what you went through. You should feel good that you were there for your family regardless of how anyone else acted. At least you always know that you can control what you do. Unfortunately, if your mom is active at the hall, she probably does not have that same kind of freedom. Don't forget how they say over and over at the meetings how loyalty to Jehovah(er, the organization) comes before loyalty to family. That can really mess with a persons head. Deep down I'm sure she knows well that you and your sister are more important than anyone at the hall, but she faces a huge social pressure to act the same as everybody else.
I was intrigued by the military comment, because I have been using that analogy to my parents in another way. They defended the religion by saying that it has changed a lot of people's lives for the better, people who were once drug users or in trouble with the law, etc. I maintain that is only true because of the high control aspect of the religion. Some people cannot or will not use any self control or think for themselves, and those individuals may do better as a jw because there is so much constant contact and pressure to be a certain way. Likewise many straighten their life up by joining the military. It's just a matter of handing over the control of their life to somebody else. It doesn't mean the religion is true, it just means that some people benefit by being told what to do all the time. To me, the religion is like a social military. The pressure to conform does not cause me to live better, it brings unhealthy stress into my life.
Darth, I'm glad that at least the surgery went well. It sounds like that brother was extremely presumptuous to be there. If it ever happens again, I would ask him directly what purpose he is serving and who requested his presence. Put the spotlight on him and make him explain everything he does. Turn it around, so he is the outsider, not you and your sister.