I don't know, this seems pretty weak... I am certainly no expert, but there have been a lot of studies, and in reputable journals, that show at least some benefit from fish oil. One study showing that maybe there is a problem with fish oil in special cases (like confusions) doesn't seem like it's worth worrying about.

Also, fish oil is well know to help with brain development. I know that a concussion is a different thing, but it seems a little suspicious on the face of it.