His eyes looked hollow and his overall appearance was lifeless.
この場合、次のような言い方ができますよ。
ーHis eyes looked hollow and his overall appearance was lifeless.
「彼の目はうつろで、彼の全体的な見た目は生気がなかった」
His eyes looked hollow で目がうつろな様子を表現できます。
lifeless で「生気を失った・活気のない」
ご参考まで!