I thought it was lack of kine it makes more sense if the phrase is translated as "my father wont dislike you because you are poor" rather than "my father wont dislike you even though you are not very nice!"
also I thought the sorrow mentioned is tuberculosis which was refered to as "the sorrow" which was shameful because mainly poor people got it! hence the reason for for the death of one and the soon to be demise of the second.

The sorrows are great traditional irish tales in which there is cursing and transformation into swans but while the allusion is there
i believe in the case of the song it refers to the illness.

Cllr

(sorry for the scrappy post but imoff to wareham FF)