His decision is certainly the sensible one, but I'm feeling a mum-like determination to see this through to the end, however bad I'm feeling, foolhardy or not.
It's raining and cool too as I set off at 9.30 to complete the trip on my own. Sadly I follow James's advice and head south through the suburbs of Basel to find the Rhine cycle route.
I say sadly, because after 45 minutes and 8 miles I'm back in the centre of the city having been unable to get onto the route - every time I got near, the roads kept turning into motorways that I wasn't allowed to ride on...
Back in the centre, I head to the Rhine and find the path straight away (which is what I wanted to do in the first place, but James is the Swiss expert!). However it quickly peters out and I'm cycling first through industrial docks and then along a rough path.
So after an hour and a half I've managed about 5 miles towards my destination. I give up and find a road with a perfect cycle route running alongside it...
I try the route again a couple of times, but it's much too indirect and the surface too uneven, so I stick to the road.
That's much better and I'm soon zipping along at 17 mph (not bad with panniers on) with a brisk breeze right behind me, following the river.
Pass through Rhinefelden and I'm back on track, having managed 42 miles by the time I stop for lunch at 1.15. I'm having to force myself to eat and drink, as I've got absolutely no appetite. I seem to be coughing up half a lung too, which can't be healthy.
But I seem to have turned into some sort of cycling machine and carry on at the same rate. Before I know it I'm turning away from the Rhine towards my brother's village.
It's another couple of hours of gentle hills, through very pretty countryside, before I arrive at his door gar ahead of schedule.
So that's our ride from Dunkerque to Switzerland done. Around 563 miles (compared to the planned 550) in 7 days.
I hope mum would be proud...
Post script: James is feeling much better and rode the Basel to Grafstal leg this weekend!
Here's a video of the day: