He was a remarkable man, an intellectual, who had witnessed first hand the horrors of the holocaust including the death of his father and a sibling. Something which interests me particularly is his friendship with "The Rebbe", Rabbi Menechem Schneerson, who was something of a mentor to Elie Weisel despite Mr Wiesel being a secular Jew, an agnostic; Elie Weisel's father came from the same tradition as Mr Schneerson so there was some early influence and that may have something to do with it.
Having gone through terrible times I can see why the Rebbe was his mentor, it ties up with the idea of the rightious gentile and the Noahide laws.
His message: become righteous
On Sunday, March 1, 1992, Gabriel Erem, the editor of Lifestyles Magazine told Schneerson that on the occasion of his ninetieth birthday they would be publishing a special issue and wanted to know what his message to the world was. Schneerson replied that "'Ninety,' in Hebrew, is ‘tzaddik,’ which means ‘righteous.’ And that is a direct indication for every person to become a real tzaddik - a righteous person, and to do so for many years, until 120." This message, Schneerson added, applies equally to Jews and non-Jews.[112]
https://en.m.wikipedia.org/wiki/Menachem_Mendel_Schneerson
The message of those that survived the holocaust is often that we shouldn't forget and let it happen again.
They value, especially value those people that helped, the rightious Gentiles.
The Rebbe also taught a message about kindness and taught about the 7 noahide laws that he thought was the basis for every civilisation.
It is relevant because It is about being good and living a rightious life, making the world around you as good as it could be, making it better.
In such a world there is no room for holocausts because it's about valuing another human being and self responsibility.
I can see exactly why the Rebbe was his mentor apart from him coming from that background
If Elie was secular, the basic teachings would have come across as a " shared humanity" no matter who people are.
The Rebbe set up the Noahide movement.
The message of the holocaust survivors is often to teach about it to change people's hearts, so they are aware of what a terrible thing it was, and that we are all human.
No one should have to go through that again.
Many Jews believe that non Jews just have fewer laws to obey.