The meeting with Berthold was only the first of many since Khan needed to relay his message to all the allied descendants' families. More guests arrived within the following day, leading to more tense conversations and threats.
Bruce, Mark, Lucy, and John's families received the same treatment as Luke's father. Their relationships with Khan weren't equal, but the conversations followed the same pattern, starting with basic pleasantries and ending with a clear threat.
That outcome was satisfactory. Truthfully, Khan couldn't expect the conversations to go any better. Also, those families mostly were on the same page, allowing for a smooth conclusion that was bound to make every faction wary of plotting against Khan.