The red light is just that - a red LED that only serves to indicate that a button has been pushed and the battery is OK.
There is NO InfraRed (IR ) interface to the car, it is all Radio Frequency ( RF ).
The key should still work to start the car, as this is done by an RFID chip in the fob ( not on the circuit board ) that should not be water sensitive.

That part about "aim the transmitters red eye at the vehicle" is pure BS.