Fan Zijin came over from the Fan Residence. Regarding his relationship with Fan Siwen these years, it had been not terrible but not that great either.
When he was not in the capital, he would make sure gifts were sent to the Fan Residence in a timely manner, only following the necessary etiquette but not a single step more.
When he was in the capital, he would go back to the Fan Residence for a meal during the holidays. When he wasn't in the mood to see Fan Siwen, he would simply go to the palace to spend the holidays with Qi Xiuyuan and the others. As Qi Xiuyuan was willing to cover for him, Fan Siwen could not do anything to him.
It wasn't that he hadn't thought of using his status to suppress him. Putting everything else aside, as long as he claimed to be sick and used filial piety to suppress Fan Zijin, he would have to return to the Fan Residence to serve him in the morning and evening. However, what was the use?