Speak with Samwell about his survival of the attack and be kind and understanding during the conversation. You should hear him mention "poor Kay Foamdancer" who fishes on the docks just outside Mermaid's Lure near The Sinking Sands carpet.
Speak with Kay at length about how she mourns the loss of her father. Be understanding and kind through the whole conversation. At the end of the conversation she will give you the book the The Mariner's Lament as a way of saying thanks for listening and because she can't bear to keep it any longer after her father's death.