Still Life: Effect of poetry on characters

When the charred arrowhead is found in his home, it is said that Matthew Croft “had finally been hurt beyond poetry.” How does poetry help him and other characters in this novel? Does it ever have the power to hurt? What do you think of Timmer Hadley’s idea that “there’s something about Ruth Zardo, something bitter, that resents happiness in others, and needs to ruin it. That’s probably what makes her a great poet, she knows what it is to suffer.”