Read it through once

Between him and her brothers slight difficulties were always arising which resulted, for the time being, in a certain coldness. For example, Kashiwagi, Kumoi’s eldest brother, in ignorance of the fact that Lady Tamakatsura was his sister, continued to pay his addresses to her, and finding that his letters often failed to reach their destination, naturally turned to Yūgiri for assistance. Never once did he offer to perform a similar service in return, though it was presumably as easy for him to see Kumoi as it was for Yūgiri to see Tamakatsura. The request irritated him and he firmly refused. Not that they ceased to be friends; for their relationship, like that of their fathers, had always been built up of small rivalries and feuds.