What you have written is technically correct according to the rules that I understand and follow. However, I would argue that it, as written, will be confusing to most human readers, and for that reason I would argue that you should restructure the sentence.
Yarpres was trying to encourage me, "Look, the head man said, ‘spend a week more on the west wall and do your job diligently.’ Good advice that, always."
I must have looked doubtful. Yarpres continued, "The head man must have some confidence in you. He said that at the end of the week, 'he would see.' I know him to be a man of his word.”
I think that this is more digestible than your example in that it does not require the reader to parse the material to get the meaning.