Willow Huntermoon
I too think that this "Grandfather" is related to the figures closest to him. I think the look on his face is saying "what now?" The young man and woman in the backs cloths seem more peasant looking than the Old man and his young daughter with the dog. I get the impression that the son has come back to him to ask for more money...I think him and his wife are opportunist taking advantage of the wealth and good will of the old man. Almost looks like the son is distracting the father while his wife is taking the money. I also too agree that this is an outdoor scene and the darkness is a symbol of taking something that is not yours under the cover of darkness. But the old man is wise he know exactly what is going on in front of his eyes and behind his back and thus the look on his face. He hopes better for the younger daughter for she has been loyal displayed by sitting at his feet and interacting with the wolfhound which could be looked as a symbol of loyalty and friendship.