FormFieldManager

class FormFieldManager
{
    /**
     * Recria fields com rebra de bloqueio.
     *
     * @param FormInterface $sourceForm
     * @param FormInterface $child
     */
    public function rebuildChild(FormInterface $sourceForm, FormInterface $child)
    {
        $iterator = $child->all();
        foreach ($iterator as $name => $child) {
            $type = $child->getConfig()->getType()->getName();
            if ($child->all() && !in_array($type, array('choice'))) {
                $subSource = $sourceForm->get($name);
                $this->rebuildChild($subSource, $child);
            } else {
                $this->lockFormField($name, $sourceForm, $child);
            }
        }
    }

    /**
     * Efetua o bloqueio de field preenchidos
     *
     * @param $name
     * @param FormInterface $form
     * @param FormInterface $child
     */
    public function lockFormField($name, FormInterface $form, FormInterface $child)
    {
        $form->remove($name);
        $options = $child->getConfig()->getOptions();
        $dataModel = $child->getData();
        $dataView = $child->getViewData();
        if (!is_null($dataModel) && !empty($dataView)) {
            if ($dataModel instanceof PersistentCollection) {
                if ($dataModel->count()) {
                    $options['disabled'] = true;
                }
            } else {
                $options['disabled'] = true;
            }
        }

        $modelTransformer = $child->getConfig()->getModelTransformers();
        $builder = $form->getConfig()->getFormFactory()->createBuilder();
        if (!$modelTransformer) {
            $form->add(
                $name, $child->getConfig()->getType()->getName(), array_replace(array(
                        'property_path' => '['.$name.']',
                    ), $options)
            );
        } else {
            $options['auto_initialize'] = false;
            $field = $builder->create(
                $name, $child->getConfig()->getType()->getName(), array_replace(array(
                        'property_path' => '['.$name.']',
                    ), $options));
            foreach ($modelTransformer as $transformer) {
                $field->addModelTransformer($transformer);
            }
            $form->add($field->getForm());
        }
    }
}

FormType

$fieldManager = $this->fieldManager;
        $builder->addEventListener(FormEvents::POST_SET_DATA, function(FormEvent $event) use ($fieldManager) {
                $form = $event->getForm();
                $clone = clone $form;
                $fieldManager->rebuildChild($form, $clone);
            });