The three Johns

A peak behind the curtain,
  and maybe a glimpse.

Reaching a certain age,
  I found myself in a unique situation.

One of my teachers was dying,
  and I found myself one of the final caretakers.

I was used to this by now,
  watching over another friend,
  but this was different.

She was apologetic,
  she had no delusions,
    but she still needed a hand to hold.

There were three of us,
  and by an odd happening,
   we were all named John.

Each of us took care of her,
  but I was the last,
    and it is fitting my name was different.