The business trip sounds important, and was possibly organised well ahead of the move. The actual completion date (i.e. move date) is usually known with only a few weeks' notice, sometimes much less (e.g. days!). Once you're offered a completion date, even if it's close to an important business meeting, you're not going to argue - you want the move to go ahead without a hitch. All would have been fine if the child had not got ill and, even though the child is ill, they're all coping. I would let it rest without comment.