Hello @Bea and welcome to our community!
"Volkshochschule" in Berlin offers a huge variety of classes for Microsoft Office programs. You can use the search tool on their website to get an overview using different keywords:
There is classes for beginners and advanced people focussing on various topics. For example here is an online class about the basics of Microsoft Word 2016:
Just pick one from the list that suits your friend best.
By the way, he will probably get a discount on the course fee since he has got a refugee status.
I hope this answer was helpful to you.