Ofc his best chance, course is good for him and yes he has second highest w/kg but Im honestly not so sure, his stats in one day races are abysmal and even more so long races above 200km that would worrie me for his case and this is over 250 km, to say he would do good without managing a top 10 or top 5 in a single big monument/classic before well its ballsy.
Well, when you're pure climber/stage racer you can't have many/any good results in races over 200 km as they rarely do 200 kilometres GC stages.