Hello Denny 28,
I am an immigration councelor and I am a foreigner too. I have made my Integrationcourse hier in Germany. The certificate Leben in Deutschland expires not. It gives you the possibility in 7 years to apply for the German citizenship if you successful finished the integrationcourse.
I hope these answers can help you and your friend to get ahead. If you need more help, you can contact me through the mbeon application. You can download it free charge. You can do this using one of the following links:
The app and the messaging are confidential.
You can find me in the app under the name: Alzey, Herr Zsigó.
Thank you for your trust.