What’s the difference between mr Tom and Willie

There are a lot of differences between the two. Willie is an eight-year-old evacuee from Deptford, a neighborhood of London. After a huge threat of bombing raids from the German Air Force in his hometown, Willie is sent to Little Weirwold, a country village in the north of England. When Willie arrives on the doorstep of Mr. Tom, he is a nervous, scrawny, and quiet little boy. Tom is a widower in his 60s who lives on his own in a cottage with his dog, Sammy. Tom has kept to himself since the death of his wife, Rachel, and baby son, William, almost 40 years earlier. He has withdrawn both emotionally and socially, and thus many of the other villagers think of him as unfriendly and reclusive.

tom is a fully groun man,willie is a child, have u even read the book?