That's because her voice was very thin, as if it would break if someone speaks against it.
I think he said "no" because the hatched is also like a weapon so the airport security won't allow him to past and he said no because he didn't think that he'll need it and he said "no" on page 9
I think on page 9 at the top, Brain did not say "no" to his mom while she was giving him a Hatchet because he did not want to displease her at that time when she came to drop her at the airport.
Ani I did not understand you!
my guestion was that why he DID NOT say no to his mother when she was giving him a Hatchet.Int I can uunderstand you and i also think that you are also right.
Brian didn't say no because, his mother might feel bad about it. I knew this because, it said"But her voice was thin, had a sound like something thin that would break if you touched it."