The team had a decent QB, and coach's son was the star WR. Or at least the coach wanted to make him the star WR.
They were neighbors and would throw to each other all of the time outside of the allowed number of official practices, so I think the coach thought that his best chance to be good soon (and for his son to be good) was to have this QB throw to his son - and that's what they did. All practice every practice and every game.

The thing is, the coaches son wasn't that good of a receiver. And the other teams were pretty quick to notice that most plays were going to be passing plays and almost every pass was going to one receiver. Over the first 3 weeks or so, the WR who was getting all of the passes thrown to him slowly started getting better and better. I mean - when every pass comes your way you start to catch a few more of them, right?

Game four - the QB gets hit hard and breaks his collar bone. Coach's son is the backup QB. So he moves over, and now we've got a bunch of WR's who have never caught a pass in a game and rarely had a pass thrown their way during practice even. It was a rough season.