YOU SAID:

he is so sad that he'd been crying for hours

INTO JAPANESE

彼はとても悲しいので何時間も泣いていた

BACK INTO ENGLISH

He was so sad that he cried for hours

INTO JAPANESE

彼はとても悲しかったので何時間も泣いた

BACK INTO ENGLISH

He was so sad that I cried for hours

INTO JAPANESE

彼はとても悲しかったので何時間も泣いた

BACK INTO ENGLISH

He was so sad that I cried for hours