I would dearly love to live in Ireland, I have been a massive fan every time I have been there, but the weather, rather too cold and wet for my preference, especially in the SW which is where I would like to be.
As far as legalities go, if he is French no problem, there is still of course free movement between the 2 countries. If he is British, maybe a bit more hassle since Brexit but the Common Travel Area agreement is still in being (though who knows when Johnson, might wreck that too).
For employment, I don’t know, if I had gone there when I was still working there would not have been a problem, HGV drivers are always required, but I doubt that the working conditions would have suited me. I think you will find that most of the Irish lorries you see in Europe today (and in Britain of course) will not have Irish drivers behind the wheel. I think that speaks volumes for the way they are expected to work and the remuneration. it may be similar in other areas of employment too.
In short, a great place to retire to if you don’t mind the weather.