I see you got an answer on the PCWorld forums. Yes, if your son got water inside the connector, I suppose it could have shorted when he plugged it in. (I won't ask why he was working with the computer with his hands dripping wet.)

But another possibility is a static discharge at some time -- I know of such drives being destroyed in this manner.

As the drive would not work in your system either, I fear the data on it is toast.