People often ask if someone else (a formatter, for example) can upload books for them, or can otherwise share some of the functions of the KDP platform, and the answer is always No.
But Draft2Digital has done it! I got this email yesterday: "D2D Account Sharing will allow you to give select users limited access to your Draft2Digital Account. So if you have a virtual assistant (VA), or have a family member or friend who manages your books on your behalf, you can now grant them access to do what you need!"
Note that it is possible to let D2D manage your books on the KDP platform. You take a slight hit in royalty (about 60 percent instead of a nominal 70) but for some people that might well be worth it, just as I am willing to give up 10 percent to avoid the hassle of managing my books on Apple, Barnes & Noble, Kobo, and other stores.
Apologies if this has been posted before. Merry Christmas! -- NJ