Boy in the Tower - spoilers wanted

[Aparecium]

Do not read this if you do not want to read spoilers.

I have to read this book, but I'm really disliking it. I don't care for dystopian tension. I've reached chapter 42 and I've had more than enough of it. Can anyone tell me the rest?

They get rescued by a helicopter in the end. Even the cat.

How does Ade's mum go out to the helicopters?
Are the Bluchers stopped or destroyed? Apart from the usual we're destroying our planet, are they an allegory for something?

Ade's mum has improved with support from the others. She becomes aware of what has been happening and talks through her trauma with Dory.

The bluchers have only destroyed London as others found out that salt kills them before they spread further. Ade meets Gaia again in his new home by the sea.

The escape from the tower is quite dramatic as the bluchers have started to get into the building (rain washes away the salt) and it's about to fall.

It's a good book! Often used as a school text.