Responses
I have noticed in manhwas that for the english translation the word nephews is used as a unisex plural for some reason. If they are referred to individually you will see the word niece but otherwise they will use nephews. Im not sure why but it may be based on an old ideology. In the past masculine pronouns used to be used for overall groups as unisex pronouns while you would only see feminine pronouns used when speaking of individuals unless the group was actually a group of females. I believe the concept may be similar but again I'm not sure.
Why does she keep saying nephew when there is also a niece?
And since her family is eliminated from looking after her kids, why not try the godmother at the temple?