With fish especially I would be concerned about texture. Everytime you thaw and refreeze the ice crystals reform furthering the break down of the structure of the fish. By smoking the fish you are removing some of that moisture so it may not be to noticeable but I am very familiar with mushy fish that has been defrosted and refrozen.
As far as the summer sausage and bacteria, if he is breaking off a chunk with his hands or grabbing a big ole bite while in the boat he is introducing bacteria. Remember bacteria continue to grow in cold temperatures, just more slowly. Toxins are not normally destroyed by freezing. Every time that food comes out of the freezer and warms up just a bit the population of bacteria will get a jump start (compared to their rate of growth in the freezer). Eventually, I don't know how long or how many times, the bacteria will grow to the point that the sausage could be dangerous. If he is using a Nitrate cure the rate of bacterial growth is slowed even further but then why would he have it in the freezer.
He would be better served vacuum packing single portions and not returning the unused portion to the freezer.
As far as MOFO's original question. How many times was the fish frozen and defrosted prior to you getting it? Fresh off the boat or part of a pack from Sam's Club? I would not refreeze the fish for any length of time. 2 or 3 weeks max after returning to the freezer, but we eat a lot of fish down here and I am picky about the firmness of the flesh.