I think Jack was referring to the last 4 messages, which occurred over a 2 or 3 hour span. this appears to have been several hours before he possibly hit the reef.A few things to consider:
1. I believe the guy on FB (who first announced Rimas' "demise") mentioned 4 fairly quick pings from Rimas, which I took to mean that Rimas was concerned about something at that point.
2. I think there is some information asymmetry. We were privy to very little information. I would have to think Rimas was in contact with Jean somehow other than through regular channels. On his previous adventures there was also that alleged router based in the UK or something like that who was feeding Rimas instructions. Going back to Point 1, I believe Rimas was not oblivious to this reef.
3. Again, I find it entirely in character for Rimas to have pulled the broken tiller plea from his Rolodex of "emergencies"
I don't think Jack had any information we don't have, which is admittedly little. IDK what private messages may have been exchanged between Rimas and Jean or others.
I agree we don't know full extent of 'broken tiller' or 'damaged sails'. Rimas certainly did have a track record of embellishment.
What we do know is that if there was a possible hazard in his path, like Donut Island or the previous one a couple hundred miles before Samoa, Rimas went on endlessly about it. In his last four messages, not a word about Texas Reef, only Noboutini. I suspect he didn't know the reef was there.