it is no taboo but does ur concience support that. will u 4 life treat ur sister's kids with the same kind of treatment u will give ur own? are u ready to live ur sister's life 4 life? are u thinking on this base on love 4 the people involved or is it pity? these are just few of many self examining questions that will drop u at the right conclusion. JACOB in the bible married two sisters. u are not taking ur sister's husband, rather u may be saving those kids from possible future child abuse.
@fidel, thanks so much for this sensible advice.Out of all advices yours is the best so poster read this twice and meditate on it well.