How do I get the "Silent Ally" from Orbeck?

[Knight Shiba]

So I know I need to buy all his spells and all his tomes, but apparaently some people have messed this up before. How do I get it without screwing up the process?

[MortalitasBorealis]

buy all spells, talk (the option) to him twice.

[Scotch]

I don't wanna copy something like "buy this and this spell" from the wiki, because I have not tested it by myself.
But what I can verify is giving him the 2 scrolls from Farron Keep, buying all now unlocked spells and finally using the talk option triggers him giving you the emote.

It's important you give him at least 1 scroll before you defeat the Abyss Watchers.

[Sander]

You need to buy 15 spells of him, price doesn't matter. After that talk to him and he will also give you a ring.

[Captain Striker (Empo)]

I thoght you only needed to buy the silver spells...