How to parse JSON

The example JSON string:

json = ExportString[<|
    "Names" -> <|
      "Sister" -> "Nina",
      "Brothers" -> {<|"Older" -> "John", "Younger" -> "Jake"|>},
      "somethingElse" -> "answer"
      |>,
    "DOB" -> {
      <|"Nina" -> 2001, "location" -> "Miami"|>,
      <|"John" -> 2017, "location" -> "Hell"|>}
    |>, "RawJSON"];

Import it as an association:

assoc = ImportString[json, "RawJSON"];

Here is how to get an association for each key at the first level:

<|# -> assoc[[#]]|> & /@ Keys[assoc]

Here is how to get a JSON string for each key at the first level:

ExportString[<|# -> assoc[[#]]|>, "JSON"] & /@ Keys[assoc]