Who is Dick's brothers and sister from One Man's Wilderness: An Alaskan Odyssey and what is their importance?

Jake, Dick's brother, is a pilot who flies up and down the California coast. His sister Florence makes Dick's curtains and pays Mary Alsworth to make him a birthday cake. Dick regulary receives mail and sundries from both of his siblings to use on his wilderness adventure. Dick also has brother named Raymond who is mentioned in the Afterword about an airplane crash they both survive in 1976.