I am afraid the issue of helping your company executives discover their own life purpose is either philosophical or religious. The answers to this question are rather subjective, as they can be derived from each individual's cultural and ideological backgrounds.
Understanding Cultural and Ideological Backgrounds
To begin with, find out the cultural and ideological backgrounds of the executives, and then provide them with information related to the purpose of life based on the teachings in their respective domains. For the religious individuals, explain life in terms of an implicit purpose not defined by humans. For example, Muslims may refer to the Quran and Hadith, while Christians may look to the Bible. For those with philosophical leanings, explain life in terms of ideals or abstractions defined by humans, such as Cynicism, Aristotelianism, Platonism, etc.
Aligning Company Mission with Personal Purpose
My humble advice to you is to first explain to the company executives the mission, vision, and objectives of the company. Then, align these with each person's life purpose, taking into account their cultural and ideological backgrounds. In this scenario, the company/organization is the most crucial aspect, and its 'going concern' is of paramount importance. This unity is the reason why you all work together as a team.
I hope this guidance helps in addressing the matter effectively.
Kind regards