Travel insurance is indeed wonderful - if you can get it where you live. If you can't, then ...
Fennel, yes very harsh. Many had planned to retire to France for many many years- some had bought property well in advance- and moved when they retired, either before the Brexit campaign- or at the start when all promised a 'Great Deal, the best Deal' ever...
Others have developped severe health issues after the move, and as said, I know many who have been widowed. S1 covered those of official UK retirement age, and they dependent spouse, even if younger. Hard enough to lose your partner, and to lose your rights too. And for many, they have put all their savings and the proceeds from their UK house to purchase the house in France, Spain or wherever in the EU, and to do the necessary renovations. They now have houses that can't sell (they were cheap because in areas where the 'natives' don't want to live) - and no savings to fall back on.
So, yes, as said on previous threads- their only choice will probably be to return to UK destitute, and request housing, social care and health care from the UK. Not sure this will be beneficial to the UK- let alone them. (and as said before, that will not apply to us- we have made sure in our plans that we left all doors opened, and the fall in Sterling and the rise in CHF- would ensure a very nice profit- but that is NOT the point). DD1 and GCs will probably move here if things turn bad for financial services in the UK- so it would be ridiculous to move back now.
We will - adapt and survive- we are VERY lucky. Many won't be able to - and yes, they are not ATBU to be annoyed and more, at those in their shared communities who actually voted for their demise. And yes, no point in asking for any empathy from GN.