JSFiddle - React, Tailwind, and code Playground

HTML

<input type="checkbox" class="css-checkbox" name="kf-eigenesDatum" value="" id="kf-eigenesDatum"/>
    <label class="css-label" for="kf-eigenesDatum">
        <input type="text" name="kf-eigenesDatum" value="" class="wpcf7-form-control wpcf7-text" aria-invalid="false" placeholder="31.12.2014" />
    </label>

JavaScript

$('input[name="kf-eigenesDatum"]').on('click', function() {
  $(this).closest('label').prev('input').prop('checked', true);
  return false;
});