I certainly don't want to sound callous about this, but is your sister a slave? Last time I checked back home, people still had the right to decide what to do with their lives in such a situation. I mean, did someone hold a gun to her head and say "Stay or Die"?
I am here in Baghdad because I chose to be, and I stay here because every day I wake up and choose to stay. There are obviously repercussions I will face if I leave before my assignment is done, but I gotta think it's small potatoes compared to being DEAD.
I commend your sister for having the guts to stay. Unless there was something very special about her situation, realize that she took the risk of her own volition, just as I do, and is responsible for that decision, just as I am for mine.
Personally, I would not consider it a wise move to stay and work for an employer who has such little concern for my welfare as to expect me to take unwarranted risks due to their lack of adequate planning. I gotta think with her skills, she would have no problem finding gainful employment elsewhere in short order. By staying to take care of critical needs, she mitigated her employer's obvious incompetence and inconsideration. I am certain that her employer is being/has been greatly compensated because of her sacrifice. Did they pass any of this windfall on to her for her devotion to duty? I would certainly be surprised if they did.
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The ultimate result of shielding men from the effects of folly is to fill the world with fools.
-- Herbert Spencer, English Philosopher (1820-1903)