Indivisible gives a good commentary on how we treat people in the US that some believe "don't belong."  It shows what we already know, ICE is alive and well and taking immigrants regardless of how long they have been living in the country and contributing to society.  But it also shows how this harms children.   
This book does a great job of walking the line of showing the trauma and giving the reader more than they can handle.  The characters are all believable and strongly developed.  Mateo struggles with having to become the head of household and still being a teenager. 

His only weakness is his inability to tell his friends.  His reasoning is understandable, but frustrating nonetheless.

The diversity of the characters add to the story.  While the ethnicity of the main character is a definitely  a plot point, the fact that he is also gay is not.  I love that there is not trauma surrounded by the sexuality of the characters in this story, it is simply a stated fact and then we, as readers, move on.   The romances are very high school like and follow a pretty common trope.  But again, this is all secondary to the main story, but adds a little bit of a relief from the stress that is Mateo's life.  I appreciate an author that has a center main plot, but adds some relief from traumatic events.  
I also love that this is a story from the child's point of view.  I think that another book from the parents' POV would also be very good, but I love the way that Mateo is able to talk about his family in this book.
Overall, this timely  book is an amazing way to show the damage we do to families when we pull them apart for reasons of selfishness.   I highly recommend this book.