Translation:The cook will have died by next month.
Most verbs in Dutch take hebben in the Perfect Tense.
• Example: "Hij heeft het gezien." (He has seen it.)
However there are quite a few verbs that take zijn in the Perfect Tense -- when the English equivalent might normally be to have.
Example: "Ik ben gekomen." (I have come.)
Refer to this guide for more information and examples: https://www.duolingo.com/comment/3859133