I guess it's not too late to add nutrients, if he started it yesterday? this is somewhat similar (gravity-wise) to my 1st and 4th batch (I think the 1st one was higher), and I've seen the yeast I have described as having an alcohol tolerance of 16% and 18% (same brand and product name), so it probably fits the bill for a champagne yeast
on the 1st one I didn't have nutrients (but added the juice of a lemon and a few sticks of cinnamon, I was following the apocalyptic knights' recipe[1] loosely), on the 4th one I used pollen for nutrients; both of those should be easier to get from your local supermarket than amazon stuff
I guess the results will depend on the yeast, but my first batch took a really long time to finish fermenting (started it in early September, ambient temperature about 28-30 deg. C, finished at the end of October), presumably due to the lack of nutrients, but it was decent when I racked and cleared it (finished rather sweet, though) and awesome when I drank the last bottle in late December / early January. Batch 4 took about a month to finish fermenting and was drinkable even before it finished, and awesome a month later.
[1]
https://www.youtube.com/watch?v=xMeSGNBOUP8 - he gets some things wrong, but still, a decent starting point