<human>: Can you summarize the given text in a few sentences?

My older sister (now 27) was a real party-girl in high school (drank, lots of promiscuity, etc.). They met at a Canadian university where they both studied. She became increasingly conservative. He proposed to her on her first trip to Europe and in ~1 year they were married. We attended their wedding in Germany but it wasn't at all accepting of any North American traditions - my parents left early, which was incredibly sad for them.

She converted after 1 year of living with him in Germany. She did a pilgrimage to Mecca (Sorry if my wording/understanding of these traditions is slightly off, I've tried to stay informed but unfortunately can't really ask questions). Since converting, she has become a total stranger to me.

During this period my younger sister (now 19) was going through a rough time. She went to live with them, which at the time seemed great and they were very welcoming and supportive. She herself became very involved in their culture - though they live in Germany they are isolated within their Turkish community. She has told me that she was becoming very close to converting... increasingly so as time went on. Apparently a lot of pressure was put on her to convert, and she was being given more gold etc.

Weeks before my younger sister was to start schooling in Germany, she returned home to Canada and started dating a new boyfriend. My sisters' husband was outraged and basically said she was a traitor.  There is a real "us" and "them" sentiment.

There is a lot of tension recently. I got in an argument with my sisters' husband, and since then my older sister deleted me from Facebook (our only means of communication). She's well beyond salvation, and maybe doesn't need to be saved if she is so happy in her new life? Is it even possible to save someone from a cult? Is it ethical? How do I handle my destroyed relationship with my sister so that she knows she has a safe place to come if they split? At the same time, how do I not feel angry and resentful. I don't know anymore... /r/turkey assures me Gulen is a cult.
<bot>: Sister converted to Islam, is now in the Gulen movement/cult. Younger sister broke free, spilled the beans. Now everyone hates each other.