When you submit the form there is a new request to the server. Because `global $loop_anwaelte;` is populated on `add_meta_box` it will not be populated on `save_post` which fires much, much earlier in the new page load. I am pretty sure that is why your "save" isn't working. The `foreach ( $loop_anwaelte as $anwalt )` simply does nothing, and if you had [debugging enabled][1] you'd likely see errors/warnings.

There are several ways to solve this:

 1. Populate the array twice, once on save and once on the meta box
    display
 2. Populate the `global` early in the page load, for example, on one of
    the [`load-{page_hook}` hooks][2]
 3. Better, use option #2 and convert the whole code base into a class
    to avoid the `global` altogether.
 4. Rewrite your form so that you are passing an array through `$_POST`
    that you can then iterate over.

Option 1) is inefficient for obvious reasons. 

Options 2) and 3) are prefered, with 3) being much, much neater.

Option 4) would have validation concerns to deal with as `$_POST` data-- all `$_POST` data including the key names-- is subject to user manipulation.
  [1]: https://wordpress.stackexchange.com/a/95983/21376
  [2]: https://codex.wordpress.org/Plugin_API/Action_Reference/load-%28page%29