I may not know better... But I thought it was a well told story, funny at times, sad sometimes but above all, it got across as sincere to me. Sometimes it was a bit slow, seemed to pause too long for dramatic effects at those points. But I loved it and I cried certain places.
The criticisms from the "professionals" seemed too much. Anyway, when Moby Dick was published, the critics of the time completely destroyed the book. Today, it's a must read classic.
I tell you, "The book of Henry" is a work of Art.