My father actually contacted me by email! Sadly, he wrote that he hadn’t anything left from his father. The only photo he had of him, has been destroyed when he was a teenager….😿So no, no letter or documents available.

At least I know now how to write and pronounce the English name correctly 😃.
But amazingly he also wrote that he never wanted to end our contact.
The last time we saw each other (more than twenty years ago) and then said goodbye, we arranged for a new meeting.