Phil, I'm not sure why you named this thread as you did.
It sounds like the weather deteriorated to below the Captains limits. Captain diverts, everyone lives - job well done.
I see no reason for "red faced" - ness!
Weather goes below my limits. I divert, everyone lives - job well done. Nothing to be embarrased about really.
he probably didn't have the level of training required for this particular aircraft."
He probably recieved the same
level of training as every other Q400 pilot. He may NOT have recieved specific Low Vis. training, or completed the required number of hours or sectors, whichever they use these days, on type to allow him to legally operate to lower minima.
And a diversion is a diversion no matter where you go.