only the brother has sex with the wife.
there is a theory I have that the brother will be in some sort of accident where his dick falls of and then maybe the wife will look MC's way, but not before the brother has impregnate her 4-6 times, since she is dicked on the regular with MC being the 10year old that he is, just watching.
it might be possible for the mc to have a taste of her pussy but it needs certain conditions to be met, ie sun rising from the west, finding the entrance to the hollow earth and/or the holly grail with the mummified hand that held it last time.