if($fh == "Harry") {
$password = "123456";
}

"Harry":"12345","Biswas":"789456","garry":"56894"

$str = '"Harry":"12345","Biswas":"789456","garry":"56894"';

$passwords = array();
foreach( str_getcsv( $str) as $entry) {
    list( $name, $pw) = explode( ':', $entry);
    $passwords[$name] = $pw;
}

$fh = "Harry";
echo $passwords[$fh]; // 12345

$data = file_get_contents("userpass.txt");
 $records = explode(",", $data);

 foreach ($records as $record) {
    $record = preg_replace('/"/', "", $record);
    $userpass = explode(":", $record);

    //DO YOUR SQL STATMENT HERE

    $sql = "INSERT INTO user (username, `password`) VALUES ('" . $userpass[0] . "','" . $userpass[1] . "')";
    //execute query
 }