Update on my friend: he's feeling a lot better today. Still in bed and really tired all the time but now not feeling anywhere near as ill.
I know no one else knows him but I thought I'd keep giving progress reports as this is (thankfully) the only first hand account I've had of the virus so far and I'd guess most people are probably in the same boat right now.
Thanks for the update, it is interesting to hear about a case in "real" terms. I'm glad he is feeling better.