what happened to evan at the end of the 5th wave

I believe the book has a strong beginning and ending. And I don't like brainless main characters. But when the main characters don't comprehend this until nearly two-thirds of the book is over, then I question their intelligence. If the reader realizes this within the first third of the book, the main characters should at least pick it up by the first half of the book. I was also frustrated by the naivety of all the main characters (which is a nice way of saying how stupid they are) when they don't / can't / won't realize not all humans are humans. The story did flip back to Cassie eventually, but by then I wasn't sure I cared anymore. And then it became about the harshness of military training - again, hard to adjust to. But then it switched to three different male characters, which was hard to adjust to. I loved Cassie - I loved the story from her point of view. But since I purchased this book based on the positive reviews and I really didn't like it, I feel compelled to state my own opinion in a review. Found myself walking alongside characters to find food and shelter and feeling just as disturbed trying to figure out how to distinguish the enemy from other humans. Their journey was a little like 'Revolution,' 'The Walking Dead,' and 'The Road' woven into a teenage tapestry of action, adventure, and the power of perseverance. Cared about the characters, enjoying alternating viewpoints and narration by Cassie and other character (no spoilers). Writing style is thoughtful, smart, and insightful. The plot is layered with well thought out details feels like peeling an onion instead of gliding the surface of most successful dystopian trilogies. Stealthy and cunning, the 'others' unleash several waves to eradicate the human race while preserving the Earth's natural resources. There are no grand explosions, little green men, or friendly visitors wishing to interact and understand our race. Cassie feels like the last human on earth after aliens have quietly invaded our planet. Anyone else over the trilogy happy dystopian and paranormal YA lit? This one stands out and is worth your credit and time.

What happened to evan at the end of the 5th wave