One or two component coatings...
I think some consideration should be given to the coating that he is going to use on the floor.
This floor has probably expanded and contracted many times over the years, and most likely is still doing that, the 2 pack coatings are very hard and once cured they do not expand and contract, and they are known to crack and lift on certain woods and in different situations like in this case, where there are seperate boards making up the floor.
In many cases the most durable and chemical resistant coatings are not the answer, this just maybe one of those cases.
I would thnk twice, and finish once.
MacS