For installing Windows-Updates on servers using command-line here is a two-liner for powershell. Run with elevated privileges 
cd C:\Windows\System32\de-DEcscript.exe .\WUA_SearchDownloadInstall.vbs
What i really like on this approach: you can select a single update-package you want to install.
As recommended by Microsoft — first install the servicing stack update (SSU):
Microsoft strongly recommends you always install the latest servicing stack update (SSU) for your operating system before installing the latest monthly security update. Installing servicing stack updates (SSU) makes sure that you have a robust and reliable servicing stack so that your devices can receive and install Microsoft security fixes.
https://support.microsoft.com/en-us/help/4490628/servicing-stack-update-for-windows-7-sp1-and-windows-server-2008-r2
References:
# https://administrator.de/forum/update-suchen-nicht-möglich-sconfig-exe-windows-2016-359185.html
# https://support.microsoft.com/en-us/help/4490628/servicing-stack-update-for-windows-7-sp1-and-windows-server-2008-r2