I had a similar situation last year. We had prolonged freezing temps and ALL of my Brugs were outside. I've NEVER had to bring them inside, so I left them out and everything froze. I lost a bunch of them, but I kept every pot and continued watering and fertilizing. I would say 65% of them came back from the roots. It is a waiting game. Some that I had in-ground died, but a few have come back from the roots. I would advise leaving your plants in ground and continuing to water and fertilize as you usually do. If nothing happens in four months, they're probably gone. You may get some pleasant surprises though. :)

They are coming back but from the roots. I just dont understand how thick & protected branches freeze at 25 degrees but didnt freeze the year before when they were 1/2 as thick & it was colder for more days.

It's really hit or miss each year with outside brugs and cold. I think it's the length of time the cold stays on them. If it's been warm during the day and you dip down to 25o in the early morning it's not as bad as 72 hours below freezing followed by snow as we had this year where I am. I covered mine and put lights under there and they still died back to the roots.