How do Bud's feeling about Herman Calloway change in the course of the novel?

When Bud first meets Calloway he finds him to be a mean, cold man. None-the-less, this changes over time. When Calloway finds out that Bud is his grandson, he becomes emotional.... he finds a link between them that wasn't there before. Bud is his daughter's child.... he's bound by blood..... the boy is family. Although, Calloway has a hard time showing his feelings, he breaks down with Bud.... he even cries. This man who'd succeeded in distancing himself emotionally has lost his focus.... he cannot distance himself any longer, and Bud was the one to break through his icy exterior and reach into his heart. In return, Bud is able to see his grandfather in a totally different context.