As far as I'm concerned, when site 2 node is down, the SQL instance in Node 2 will failover to node 1, and node 1 will keep running. We need to ensure the Node 1 could access the file share witness.
Although SQL cluster can keep running with one node + wintess, it's recommended to add at least two nodes in each site, so the cluster may have more fault tolerance.
Thanks for your time!
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