Why is Holden left on his own when he finds out about Allies death?

Allie is the one person (besides his sister) that Holden felt connected to. He was Holden's ideal, and Holden's fondest memories revolve around the love he bore him. Holden's parents shut down, and they weren't there for him. He broke all of the windows in grief and frustration.... and because he needed moral support. Holden is sent away to school because his parents simply can't deal with the entire situation.