Answer
J.B.S. Haldane is an altruist who can go to any extent for the well-being of others, even at the cost of his own life. Thus, when he says that he will lay down his life for his two brothers and eight siblings, he means that his altruistic allele would still pass on to his future generations.
Work Step by Step
Altruism is the selfless behavior shown by an individual that encourages it to help others. This is a rare characteristic that may be easily lost in the population. The coefficient of relatedness between an altruist and the siblings (recipient) is generally 0.5 and 0.125 between an altruist and first cousins (recipient). To retain the altruistic gene or allele, the donor needs to save either his/her siblings or first cousins in future generations.
