Sounds like a non event to me. Lots of airports were open, sounds they had other options available, just had to decide where they wanted to go. Guess the crew wanted to consider best options prior to informing ATC. Normal practice surely. Ask ATC for diversion to planned alternates. None available, come up with a new plan. I wouldn't have expected them to come straight back with a new plan, I am sure they wanted to get some more info/ discuss it.
Why would he have been boxed in at this stage? Other airports available and sounds like they had enough fuel if they were asking for MAN.