Does anyone know how "gifting" works with GoG?
Specifically, I'd like to get in on these deals and gift them to my brother, but for Christmas. Is there an option to delay the gift until a later date, like Steam does?
Or could I buy them for MY account, and he could just log in with my details and install them to his computer?
For what you're wanting to do, you can gift it to yourself (GOG account email).
You'll get the code link in your email, which really you can ignore, since you'll also have the code in your "Gifts" tab.
You can see the "Gifts" tab when you go to your Library (under Account), and from there along the top you'll see Games, Wishlist, Gifts, Messages, Settings.
Codes brought on GOG don't expire, so you can essentially hang onto them as long as you need.
To redeem the game/code, there is an option to resend it where you can probably change the email - I haven't tried this.
What I do is just send the code that you can see, which is easy to activate.