I wouldn't worry about your child -- sailing passages take much longer than most land-dwellers realize, and it's not unusual for boats and crews to go incommunicado for lengths of time that would seem unthinkable on land.
Also, we are familiar with the Floating Doctors, and have seen more than a few photos of their vessel. It appears to be reasonably stout, but probably not the fastest passagemaker. So they could be out there a bit longer than average on their crossing to Haiti (if that's their destination?)
I know as a mother you can't help it, but please don't worry too much. They'll be fine.
If you ned help of any kind, feel free to post here.