Looking at the videos, looks like they lost propulsion and were sitting beam to. The boat appeared to be doing fine until a big breaker came through and rolled it.
As best I can determine after flipping through tons of pictures, the boat appears to be an Ocean Alexander 460.
Most impressive to me is that while it appeared to have significant damage from the roll (and likely far worse than we can see in the videos), it rolled all the way through and finished upright. Better than I would have expected for a typical unballasted motoryacht type. The whole flybridge and aft hardtop appear to be gone, but the cockpit doesn't appear totally full of water. Can't tell if the side window survived the roll or not.