Change the narration: I told him that he was not working hard.

I said to him "he is not working hard."

I told to him "you are not working hard."

I said to him "you are not working hard."

None of these

Direct speech of "I told him that he was not working hard." is:

"I said to him, 'You are not working hard.'"

"He was" in indirect becomes "You are" in direct.