When Jim Evans says “it's a hard blow,” he's speaking metaphorically. What he means by this is that the death of the speaker's little brother in a car accident has had a terrible impact on the boy's father. At the same time, these words can be seen as a pun because the dead boy was killed by a literal hard blow.

Jim Evans has unintentionally made a link between the child's tragic death and the immense grief it has brought to his family. The literal hard blow that killed the boy has inflicted a metaphorical blow upon his surviving relatives. The blow may not kill them, but at the very least it will cause them an awful lot of emotional pain.

One could also say that Jim Evans's words show how people can often find it difficult to say the right words in the wake of someone's death. Jim doesn't intend anything by his unfortunate pun; in fact, he's probably not even aware that he's playing with words.

But his somewhat clumsy expression would appear to indicate, at the very least, that he doesn't know quite what to say in the face of such overwhelming grief and tragedy. Jim's not alone in this regard, for so many of us find ourselves in a similar situation.