Which guy was Waxer?

Waxer was the guy who tried to act gay to avoid induction and was vindictively sent to the front lines for it. No one else went to his funeral because once the surfers left the beach, or "moved inland" as it were, they lost contact with one another quickly. Yes they were close friends, but if you aren't in the line up where the good waves are breaking, surfers tend to have an out of sight, out of mind attitude sometimes. They are young and living in the moment, until of course one of them dies and the specter of growing old or growing up becomes real.

It's possible none of the main trio had ever been to Waxer's house before, or even knew his real name except by chance. None of that mattered on the water. Matt's character (JMV) is clearly the protagonist and so it was more dramatic to place him as the lone outsider at the funeral. William Katt's character Jack is presumably overseas fighting the war himself at the time, and Leroy is mentioned as being "up north" someplace searching for bigger waves at one point. The implication is that Leroy is a fugitive from the draft, possibly, hiding out in northern California in a remote location.

Story-wise, they are three kings - Leroy, a king in exile, Jack is off on the Crusades and Matt is a King Lear figure, out of his mind once he leaves his throne and lost in a storm, madness threatening more and more by the day. Having Matt alone at the "square" funeral shows he alone is facing reality, fighting to come back - Like the Bear would say, "you're always alone" when you face the biggest challenges (like big waves, or life/death itself)

The father of Waxer is clearly in opposition to Bear, their spiritual father, and the man seems surprised to know that Waxer had any friends at all from the beach when Matt tries to introduce him self and give condolences. This awkwardness sets up the nighttime visit to the cemetery by the trio as an example of an alternate funeral, one held the tribal way - wine and stories instead of pomp and formality, something Waxer clearly never cared for anyway.

More importantly, it sets up the tension for the audience wondering if Jack will return from the war, and if any of the trio will show up for Big Wednesday.