"imperial doctor Xilaile", why does Xilaile treat Wang Tianhe?

Hilaire is a doctor. His vocation is to save lives. In his view, when a doctor meets a patient, he should put aside personal grievances and do his job well. Xilaile's personal quality is relatively high, so he also has a good medical ethics. His heart will refuse. But after the passage of time and the changes of the times, he finally put aside the past, returned good for evil, and prescribed medicine for Wang Tianhe. Helal also wants to prove his inference and medical skill. Because Xilaile saw Wang Tianhe's calligraphy in prison and saw Wang Tianhe's illness between the lines. Unexpectedly, Wang Tianhe really got the disease later, so Helal still wanted to try.