Non-parent speaking.
I guess that, if this journey is a one-off, then there is not much more by way of precautions. The only one might have been to ensure that the child had local money to pay for phone calls, or could make a reverse charge (collect) call. That will depend upon the child, of course.
If the route is to be travelled more often, then a mobile (cell) phone with a pay as you go SIM for the destination country will allow the child to be telephoned by parents/guardian/greeter.