I bought this book for my niblings for Halloween and we just now got around to reading it. it's a chapter book of almost a hundred pages, with illustrations on each page. we split it between two days (but only read two chapters the first day and then read the last eight the next day haha).
I thought the book was interesting. you find out early on that Zeke IS an alien, and his next-door neighbor, Harris, picks up on it. Harris tries to talk to his best friend, Roxy, and his parents about it, but they don't believe him. the book clearly wants to address xenophobia and human intolerance of those different from them, and there were some great lines from Roxy and Harris's mom. the first time Zeke explains a cultural difference to his class (he whistles outside the door instead of knocking), Harris says, "weird, huh?" to Roxy and she replies, "I think it's kind of interesting." a different time, Roxy says, "Just because someone is different doesn't mean they're weird" and another time his mom says, "He might be different, but that's no reason not to be his friend."
these are great messages for kids. and maybe it's a bit more accessible or interesting for them bc they know Zeke actually IS an alien, while the characters in the book don't. I expect in the subsequent books, Harris will learn more about Zeke and they'll become better friends as Harris connects with him more and sees past their differences.
my last note is that Harris and his family are Black, while Roxy is Latine (based on her last name being Martinez and the way she's illustrated), so I think it's significant that both these characters who become friends with Zeke likely have their own experiences feeling different or othered. Harris's mom lightly mentions this at one point, so that adds an interesting dynamic to the story. it presents a great opportunity for adults to discuss xenophobia, racism, and othering to the kids they read to or with. all three children might share that reality, even though their identities are distinct.