I don't feel so bad for him because he never paid much attention to his health.
Zoroさんの英文、There's no room for sympathy because he did not take care of his health. で良いですよ!
または次のような言い方もできます。
ーI don't feel so bad for him because he never paid much attention to his health.
「彼はあまり健康に注意を払っていなかったので、彼のことをあまりかわいそうに思わない」
ご参考まで!