...sorry that you have been on the receiving end of some of that.
In 1978, my 23 yr old brother died in a scuba diving adventure that ended badly. Less than a month later, one of my uncles by marriage (the husband of my mother’s second sister) had a fatal heart attack while jogging. The middle sister responded to these events by saying, “Well, I guess no one is going to be happy until someone in my family dies.” She later also told me that I owed my parents a grandchild because my brother had died - not a good reason to have a child, and I wasn’t even married then.
What your one sister said about the God she believes in needing to kill your brother so the sisters could reconcile is ridiculous. I fall into the agnostic category, and one of the biggest reasons for that is that I simply cannot believe that any supreme being that might possibly exist would be as petty and mean spirited as to teach lessons, so to speak, using cruelty as a method of instruction. When my brother died, one friend said something about, “God must have needed your brother with him really bad to take him now (or words to that effect). It was of no comfort at all.
People who believe in god often describe him as a loving father. Would a living parent teach lessons in this manner? I think not.
I wish you some serenity and also some distance from those who would add to your distress by their thoughtlessness.
We don’t know each other, yet I hope you will accept a cyber hug from a stranger - 
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