This is no longer available on patreon, only when it was first released, so it would need to be purchased separately from patreon. This should explain how it works:
Every regular pack gets a patron download when they are first released. Patrons at that time can then download them for free. This rewards those who are already patrons before new packs are released. As long as you are a patron -- you'll get access to the download key for any packs as they are released during that time.
These release keys are revoked after 2-3 months. That way, latecomers can still have access to the downloads, but they won't be up forever. New patrons are welcome to download these packs if the link is still available in the archive, but it isn't guaranteed to always be available.
The FAQ thread on my patreon page lists all the packs that are available to patrons, there's a bunch that are always available as patron bonuses, this timing is for the major releases like this one.
Thanks!