In terms of kin selection, should you sacrifice your life to guarantee the survival and reproduction of your 5 nephews?

Yes. It is a fact that the genes that I have are also found in the genes of my 5 nephews. Thus, if a situation calls for me to choose, it is alright to sacrifice my life taking that there is a higher percentage of survival of my nephews passing on the genes to the future. For instance, in a sinking boat scenario, the boat can only hold up to 5 people and we are 6 in the boat at that moment. In the kin selection, I will be willing to sacrifice myself for my 5 nephews to survive. This is for the greater good and even if my existence would perish, I have 5 individuals carrying my genes which would continue to survive.