Actually, now that Kong Wen is dead, Kong Xing naturally wants to seek justice for his fellow apprentice, but he must also figure out the full story behind the incident.
Therefore, whether it was Ye Weiming conducting the autopsy, or it being this young man named Zeng Aniu, it made no difference.
After all, however they inspected, they would ultimately have to provide a reasonable and sensible explanation for Kong Wen's death.
And Ye Weiming suddenly suggesting that Zhang Wuji help with the autopsy was actually to boost the latter's reputation.
After all, Zhang Wuji was his undercover agent placed within the Ming Family!
Since there was an opportunity, Ye Weiming of course wanted to enhance his reputation in both the Ming Sect and the entire Martial World during this mission.