I believe that the part that uses the satirical tone is the part that criticizes old, sickly people. Hope this helps!<span />
He is enthusiastic and in awe while she is doubtful and fearful.
In the passage he says that he felt "strong and exhilarated" while he explored the swamp. The women, however, talks about how people have gone missing in the bog and she's surprised he ever made it out. It also says that the woman doesn't understand "how plants could draw [him] to these awful places". Because the woman doesn't understand his fascination with the bog, it's clear that she isn't interested in the bog and doesn't admire its intense dangers and true treasures.
"Then" is used in an "if-then" scenario, to dictate chronological order. In other words, "If you jump off, then you will fall," or "he was attacked and then retreated."
"Than" is used for comparisons. In other words, "The egg was bigger than the pea," or "I'm stronger than you."