Immigration Site

I have filed I-130 for my dad (see my signature). My mom passed away 11 years ago.
We dont have his marriage certificate since they were over war periods and moving, so it lost. However, I can get 2 affidavits from relatives, my aunt and uncle.
My father situation now is, hes living in Germany, but not yet a permanent residence (we are not German).
However, he is getting a permit to live there which is renewed every six months. Hes also receiving housing and food benefits.
So, here is my main concern and question. Will he has to be back to my own country for interview or he will be accepted to be interviewed at German Consular?

Thank you in advanced for any response.

What is his status in Germany? Has he got asylum or refugee status?

Thank you for the response.
However, I am not sure what his status is so far. He has been living there over 10 years now.
He receives a permit for every six months from the government. He also has housing and food benefits like I said above post.
I will ask him if he knows anything about his status there.

I just made a research on my dad status and find out his status may be Asylum.
I read the article "National Asylum and Return Policy of Germany" from erso-project.eu
... at During Stay section, the statement is showing what exactly my dad currently is now.
So, my question is if my dad status is Asylum, whether or not he have to return home for the interview?