Have lost one ex-student to meningitis across the course of my teaching and that was devastating. She was so bright and ambitious and I only heard about it through the grapevine. My best friend (also a teacher) lost a young student, he was about seven and had a brain aneurism. Not only did she have to unpack her own grief, she also had to deal with the remainder of the young people asking questions she couldn't answer. It hit her hard.
I can't believe you've lost so many, there are many times I've been thankful for not being a US citizen and this is one of them. Hopefully no more empty desks and emptied folders. Excellent article and profoundly sad. :o(