After the FB friend request, I sent him this message
Hello Uwe, we have a mutual acquaintance. @regenerette and I have been chatting in the Hive Blockchain, and she told me you helped her with a new device and treatment. Sounds interesting and I'd like to learn more
I'll write him today. We do live on different time zones.
I hope he will give you the info that you need.
Hugggs!