Somehow the stewardess comes off a bit too much as a self-centered power-hungry ego-tripping bitch. And there doesn't seem to be a statement of the airline or the stewardess herself, only the mother's side.
I do suspect the stewardess was the first to make a bad move. However, I think both parties handled it very poorly from there on.
And TotalMILF: I hope I never get on a plane with you
If the toddler is so very tired and inconsolable after 11h, you should look into ways to get him to sleep imho, for his sake, his mother's sake, and right behind for everybody else on the plane.