package Child;
...
sub AUTOLOAD {
    my $self = shift @_;
    (my $method = $AUTOLOAD) =~ s/^.*:://;
    return if $method eq "DESTROY";

    if ( $method eq 'child_method' ) {
         # do something
    }
    ...
    else {
         $self->SUPER::AUTOLOAD($method, @_);
    }
}