How is he going to feel after another 150 days? Camping in winter can be fun, but it's not warm. At all. Trying to work in a van when it's below freezing outside will be pretty hard work. I can't even type when the room drops below 15 degrees. Vans like the one he has are basically uninsulated steel boxes - they get cold pretty fast.
BTW: I bought the van in February and already worked and slept in the van while it was freezing cold: https://ruby-on-wheels.github.io/blog/the-first-ride/ it was ok.
You must be joking ;-)
I've spent 4 winters in the Algarve. While they don't get the classic beach breaks of SW France (Hossegor, Seignosse, Capbreton), there are some excellent spots down there (the point breaks at Arifana and Zavial in particular). Also, when massive winter swells come on the west coast (i.e. too big to surf), drive 30 minutes to the south coast and enjoy glassy perfection.
Locals have no problem dropping in on you, however; not as civil as the French are in that respect, but can't blame them, spots can get crowded.
Depends on the country. There are places where winter is like 30 degrees. And you can always have a portable heater -- in a small van it will heat it up completely.
And the problem is that weather is not independent. If it's very cold in Portugal for a few weeks it's usually also cold in much of the rest of Southern Europe.
In places like Malaga, Crete, Cyprus, etc it's the average low temperature is like 10-13 degrees (52-55 f). Hardly very cold if you've ever experienced NY, Chicago, Canada, Norther Europe levels of cold. And of course it's very easy to heat a small van.