Sorry for my English input. It's faster this way.

Lureen(his wife)'s version of Jack's death is that Jack was pumping up a flat tire when the rims of the tire flew out and hit his face, broke his nose and knocked him unconsious. By the time someone found Jack, he was drown in his own blood.

However, according to Ennis's childhood memory(about one of the two tough old gay men down home being bashed to death), Ennis thought Jack was killed by a tire iron by some gay bashers. The short story didn't make it clear whether Lureen was telling the truth or Ennis's imagination was tin fact true.

You are free to pick your interpretation.

I'd rather believe Jack died of an unfortunate accident than a victim of hate crimes. Otherwise it'll be really sad sad sad....