My Sister Lives on the Mantelpiece by Annabel Pitcher (2012), narrated by David Tennant
Desperate for his mother's attention, Jamie attributes her continued absence to her boss Mr. Walker not letting her have time off. When he receives a birthday package from her with a Spider-Man shirt, he wears it all the time. His persistent optimism is so sad! His sister Jasmine is older and more grounded in reality, but doesn't want to dash Jamie's illusions. Their fierce loyalty toward one another was the very best part of the book.
I knew Jamie would learn a lot of painful truths in the course of the story, but he also gained a great deal of strength and confidence, thanks in no small part to his sister Jasmine and his fearless friend Sunya.
The audiobook is brilliant narrated by David Tennant. I was a bit dubious at first: a middle-aged man performing a first-person narration of a 10-year-old boy? But he captures Jamie's exuberance and humor just perfectly. (It also doesn't hurt that I just like listening to British people talk.) The musical interludes between each chapter were unnecessary and a little too long, but even that couldn't detract from the excellent production.
A really lovely, sweet book about family and friendships and growing up. The audiobook isn't available at libraries in my area (I got it from audible.com) but it's absolutely worth seeking out.