I'm a bit rusty with XML but, if I understood your request, this deletes unwanted elements

use strict;
use warnings;
use XML::Twig;


my $twig=XML::Twig->new(
  twig_handlers =>
    {
       'dob'  => sub{ $_->delete;},
       'dobs'  => sub{ $_->delete;},
       _default_ => sub{ $_[0]->flush },      
    },
  pretty_print => 'indented',
  empty_tags   => 'normal',
);

$twig->parse( *DATA );

__DATA__
<?xml version="1.0" encoding="UTF-8"?>
    <record category="B" editor="" entered="2000-12-04" sub-category="
+PEP" uid="7320" updated="2018-12-12">
        <person ssn="" e-i="E">
            <title xsi:nil="true"/>
            <position xsi:nil="true"/>
            <names>
                <first_name/>
                <last_name>BA</last_name>    
            </names>
            <agedata>
                <age xsi:nil="true"/>
                <as_of_date xsi:nil="true"/>
                <dob xsi:nil="true"/>
                <dobs>
                    <dob xsi:nil="true"/>
                </dobs>
                <deceased xsi:nil="true"/>
            </agedata>
        </person>
        <details>
            <id_numbers>
                <id loc="INT" type="">fd</id>
            </id_numbers>
            <place_of_birth xsi:nil="true"/>
            <locations>
                <location country="df" city="re" state="">Shahrara</lo
+cation>
            </locations>
        </details>
    </record>
[download]

The output will be:

<?xml version="1.0" encoding="UTF-8"?>
<record category="B" editor="" entered="2000-12-04" sub-category="PEP"
+ uid="7320" updated="2018-12-12">
  <person e-i="E" ssn="">
    <title xsi:nil="true"/>
    <position xsi:nil="true"/>
    <names>
      <first_name/>
      <last_name>BA</last_name>
    </names>
    <agedata>
      <age xsi:nil="true"/>
      <as_of_date xsi:nil="true"/>
      <deceased xsi:nil="true"/>
    </agedata>
  </person>
  <details>
    <id_numbers>
      <id loc="INT" type="">fd</id>
    </id_numbers>
    <place_of_birth xsi:nil="true"/>
    <locations>
      <location city="re" country="df" state="">Shahrara</location>
    </locations>
  </details>
</record>
[download]

L*