Preload game files via family sharing

[NIIV3X]

So I preordered the collectors edition of Sekiro, arriving hopefully tomorrow on schedule. It containing the physical imprint of my key, I am unable to preload the game on Steam. My buddy just bought Sekiro on Steam, preloading it rn. Am I able to download the game files if we shared accounts, entering my key tomorrow, gaining full rights to play the game then without sharing? Or are the files I download locked to his account only and my attempt to not get mocked by my ridiciously slow internet is futile?

[cSg|mc-Hotsauce]

You can't, no. Not until you own the game or it is released. Whichever comes first.

[Cathulhu]

You could copy the whole shebang your friend already has. Gamefolder and ACF file. No need to use your account elsewhere.