The seat belt is irrelevant to your point. I have no view on whether at 97 the Prince is a competent driver or not. One accident doesn’t tell you either way. Lots of drivers have collisions and in most cases unless there is serious injury will be driving again within a few days.
I think you’ve missed the point all together , the poster was lambasting the injured woman for being upset implying it was because Prince Phillip hadn’t apologised personally . She obviously thinks Phil was at fault , the interview I saw with her she was more upset he was driving about without a seat belt which shows a certain disregard for the law and his own safety , which does bring in to question Phils driving competency. He is not an ordinary member of the public he has access to advanced driving chauffeurs