I know what that's like. I had three children. The oldest, Thomas, died exactly one year ago. He would've been 25 this year. He was a 3rd gen AOS (Agent Orange Sickness) patient, globally challenged, and on borrowed time since birth. My 2nd son hated him, and my youngest both feared and pitied him.
After my children and I fled from their dangerously unstable and abusive father in late 2013, I was their sole caretaker. I could not sleep if any was awake, to protect from eachother.