is he supposed to die?

"No matter the precautions you set up before you talk to Chauncey, the assassin still kills him at the end of dialogue. As soon as Chauncey closes dialogue, the steam room door opens. Quickly closing it causes the initial attack from the assassin to fail, but after a few seconds the assassin will simply shoot him through the door. Even attacking and killing the assassin before this second attempt will simply result in Chauncey dropping dead from a scripted effect. This makes it impossible to save Chauncey."
- Wikia

The assassin is in a room beneath the suana that can only be accessed by toggling collision. I wonder what would happen if you go down there first and kill the assassin before you talk to Chauncey?

-Gunny out