Who is Lonny Petersen from Our Only May Amelia and what is their importance?

Lonny Petersen is a neighborhood friend of May Amelia's. Lonny Petersen is mentally slow. Many of the neighbors think that Lonny's problems stem from a time when he was a small boy and he was caught playing in the river when the logs were released up river by the logging camp. The boy suffered terrible injuries, but eventually healed except for his mental slowness. Toward the end of the novel, Lonny's mother dies in the scarlet fever outbreak. Lonny's grief gives May Amelia something to focus on and helps her overcome her grief for Amy Alice.