Responses
probably cause they have his blood
Humans are awkward creatures. The aunt seems like a hot-head, so she probably just indiscriminately hated them all at that point, reason or no. =v= Plus if the stepmother had won her stepdaughters over, no telling the havoc that could be wrought.
Wouldn't it make more sense for the aunt to only hate the dad? He's the one that married another immediately after his wife's death. Why would she hate the children too, since they're her sister's kids?