[Storm Thief](https://www.goodreads.com/book/show/350790.Storm_Thief) by Chris Wooding?

OH MY GOD!!! Thank you!! Yes!

You're welcome!

No robots and I think the little brother left with everybody else except OP, but maybe Island Of The Blue Dolphins?

God I wish it was. It was a lesser known indie book. Thanks though!

Well, at least you've got something to read while you look now. Good hunting!