Touring in a surfski

I think I got it
You said “how would this have turned out differently in a sea kayak?”

I said if they had been using sea kayaks (or possibly even more stable skis), the others could have carried him on board even if he lost his kayak. According to their own account this was not possible with the skis they were using. So that is one way it could have tiurned out differently. They could have either tried to paddle him to shore on deck (probably not making much headway) or they could have at least gotten him out of the water and provided a bigger target for S&R to find once the others reported them missing.

Also, an overturned kayak will not blow away as fast as a surf ski, so they might have been able to overtake it and tow it back to the swimmer. Even if they had been able to catch up t the ski, they might not have been able to tow it back if it lacked tow points (if they had been carrying tow gear, which they undoubtedly were not). So that’s another possible way it could have turned out differently.

But what led to this tragedy was not the use of skis, that just limited their rescue options even more once things started unraveling. It was the lack of viable safety alternatives/plans/equipment/clothing that was the real problem, and a group of similarly prepared kayakers might not have fared much better in the end. But they would have had slightly better options.