John Gill Commentary Genesis 29:15

"And Laban said unto Jacob, Because thou art my brother, shouldest thou therefore serve me for nought? Tell me, what shall thy wages be?" — Genesis 29:15 (ASV)

And Laban said to Jacob, because you are my brother
Or nephew, his sister's son, (See Gill on Genesis 29:12):

should you therefore serve me for nothing ?
nearness of kin was no reason why he should serve him freely, or for nothing, but rather why he should be more kind to him than to a stranger, and give him better wages:

tell me, what shall your wages be ?
by the day, or month, or year; signifying he was willing to give him anything that was just and reasonable, which was very well spoken; and this gave Jacob a fair opportunity of opening his mind more freely to him, and for answering a principal end for which he came, as follows: