If this wasn't a child there would have probably been a living will in place before this operation.
Tragedy, but the parents have dragged this out and tortured themselves more than they needed to IMO.
My prayers and best wishes to the family.
I'm not a medical expert so I cannot comment that way, but I lost my younger brother to a massive brain aneurysm in August of 2012, and have family with medical backgrounds who went through painstaking detail in explaining to me how my brother's body was shutting itself down after brain death - despite being on life support.
Once the brain stops functioning and communicating with the rest of the body, it's only a matter of time before major organ failure sets in. Either way, death is imminent. It's just a question of time.
I certainly have sympathy for Jahi's family. I agree with you that it's a tragedy that they've dragged this out so long and tortured themselves. No one wants to lose their child -- especially after a surgical procedure that's so routine that it's literally inconceivable that someone would die because of it.