It doesn't look like it is one of the more tidal flood-prone areas, but like most of the Peninsula it is in a flood zone. The listing agent can find out more details from the landlord about the property's flood history, so I would ask. Also, make sure you investigate renter's insurance - and flood is usually a separate renter's policy!
148.5 Coming Street is in Radcliffeborough. As a renter, I would not be overly concerned. As long as he is not in the habit of driving right into the flood waters, he should be fine. I've heard some pretty unbelievable stories of students (who clearly are not paying for their owns car) who drive right into the deepest waters and wonder why their car is totally flooded. I would assume that the rental property is elevated on a crawl space and his residence and belongings will be fine once the tide goes out. Mayor Riley is fixing the flooding problem in Charleston anyway.