SQL Server Standard Edition Failover Cluster Installing Windows Updates
Yes, that is how we need to roll out patches in the sql cluster with minimum downtime. The downtime will be during the failover part.

Process:


Patch the passive node first.
Move the resources to the passive node.(This will become active now)
Patch the current passive node.(It was originally active).


Before doing this do test it in a Test environment and prepare a full proof plan.

Also refer to this link :

https://blogs.msdn.microsoft.com/john_daskalakis/2014/09/05/how-to-install-a-service-pack-at-a-sql-server-2012-failover-instance-best-practices/