LHN,
Going on what is mentioned in the previous post, the seas were 4-5ft at the time, so relatively rough. I am not sure what the weather and water temps are currently like in the area, but did see the man who was rescued was treated for mild hypothermia. This is by far the most immediate risk I can think of for someone drifting in this situation. How long someone can tolerate drifting varies from situation to situation, but it largely depends on the type of exposure protection he is wearing, such as how thick his wetsuit is (or if wearing a drysuit), his body fat percentage, water/air temps, if he has an insulated hood on, activity level, and general mental stamina to cope with the situation. Dehydration is also another major issue as the recommended daily intake of water for men is 64 oz. In general I would say the environment is your most immediate threat, leading to hypothermia, dehydration, and exhaustion.
To answer another question, yes, he could have been swept outside of their search area, or they may have missed him when searching in the rough seas. There are a lot of factors at play here, but if you are drifting at shoulder level in the water, not wearing anything bright, no surface marker buoy to signal with, no light or strobe to gain attention, and the seas are rough, the likelihood you will be seen is diminished. However, its really not possible for him to be swept up the eastern side of the state because the circulation in the gulf along the west coast moves from north to south so he isn't going against the current. The Gulf Stream flows up the east coast of florida between the coast and the bahamas, so this is the likely direction of travel.
Don't lose hope, anything is possible. As you can see this board is very concerned with diving accidents and a swift positive resolution is always hoped for.
