My partner works in behavioral field and this is pretty much spot on, there's not much the airline could have done.
The family wasn't denied flights out, they just made the hard decision to not put any more stress on Elijah or passengers / crew on other flights. Unfortunately, that's sometimes the choices that have to be made here. It makes the story so much more heartwarming because it looks like a whole bunch of people just trying to do what's right to keep everyone safe and happy.