Ignoring me then, eh. Well then, working from the information here...
Let us state that each life is a quarter. Therefore,
1 Qt = 1 Life
We assume the wife is pregnant, and thus she accounts for two lives. As they are married, the wife and man are vowed to eachother and belong to eachother. Now then, if the man does not have any quarters, then it stands to reason neither his wife, nor his child, nor he himself can survive. If he had a quarter, then he could purchase his own life, as the wife and unborn child come as a set.
Two quarters buys him the wife + child set. However, if he has three, he can buy ALL THREE lives! However, someone must die in order for the child to be birthed: he and his wife are wed and belong to eachother, and so share a quarter each. If he has two quarters, then he himself dies and the child can be born, inhering the man's quarter.
If he wants to life AND have his wife and child, he must therefore take another quarter from somewhere, and that source is his brother.
Does that come close? :V