This scenerio sounds a little fishy to me, and I think there is more to the story. I have had my CHL since 1995 and have never heard anything about not being able to carry on a lake. To make a very broad and general statement, every single Texas game warden that I KNOW are a**holes, and it sounds like your friend had a run in with another one.

Your friend should feel lucky that he got his gun back without a legal fight and should probably not go back to the lake with his gun in the boat.