What is the irony of the good luck Huck thinks he has been favored with in visiting the house of death in The Adventures of Huckleberry Finn?

Huck initially feels the frame house that floated down the
Mississippi to the island he and Jim were inhabiting was a piece of good luck because of
all the useful supplies they were able to collect from it. Huck manages to avoid looking
at the dead man while they ransacked the bedroom, and Jim refuses to speculate about him
when Huck wants to discuss his curiosity about him the next day. Huck insists that the
house was good luck in spite of the dead man.

Huck changes
his thinking when the mate of the rattlesnake he killed and left to trick Jim bites Jim.
Watching Jim go through the effects of the rattlesnake poison thoroughly convinces Huck
that the house was bad luck, although Jim says there may be more to come. And, of
course, eventually Jim informs Huck that the dead man in the house was Huck's Pap, which
was sad news but possibly good luck in the long run for Huck.