While storm surge is serious - it is only a worry for those living on barrier islands or on the shore of the waterways between the islands and the mainland. That's why there is always mandatory evacuations for the islands. The storm surge is really just extra high waves - Florida builds homes within 50 - 100 feet of the ocean or gulf. 12-15 foot waves cross all that flat sand, rush up the sand dunes and hit the buildings. That's what destroys so many of the beachfront buildings. Those buildings on the inland side of the barrier islands have a good deal less damage. There, it is mostly wind damage.

I would say you dad should evactuate if he is:

in a mandatory evacuation area
in a mobile home
in an area already flooded
in a wood framed home older than 10 years
if his roof sustained any damage in the previous storms
if nearly all of his neighbors are getting out

Otherwise, he's probably ok - but hey, probably ain't a good enough assurance for me - there are shelters close to his home. Have him go there - they have generators, tv, hot food and nice people. He'll probably make new friends. Bring a deck of cards and candy.

The other thing to remember is that fire trucks and paramedics will not go out to nearly any 911 call if the wind is blowing over 40mph. If someone has a heart attack in the middle of the hurricane, they are really in truoble, but all shelters have nurses, paramedics to help anyone there.