The proper relationships are as follows;
Angela - mom to Grace and Sophia, aunt to Jay (mother's side, not related to Jay's father, which is why she doesn't show much reaction to the news of his death)
Grace/Sophia - twins/sisters, Jay's cousins
Beth - Jay's sister (half-sister), Grace and Sophia's cousin
And unlike what a previous poster had stated before, Beth's relationship variable is not tied to Grace or Sophia.