In the letter, he told her, just that he must return to help his family. He doesn't want to, she was worried and hope that the problem will be handled, and will come back to meet her as soon as possible.
In a letter he had just told her that he had to return to help his family. He did not want her to worry, and hope to tackle the problem and she will come back as soon as possible.
In the letter, he told you just how he to return to help his family. He didn't want you to worry and hope to address the issue and come back to see her as soon as possible.