It really depends on what he needs and want to achieve. I host a Jellyfin (FOSS Plex) instance for me and some friends so I pay around 10€ for a VPS + 50€ per month for 20TB storage at hetzner alone (can't host at home because I only get 50k upload), but he most like won't need that if he is just hosting it at home for himself.

So assuming it's just him or people in his household using what he needs is:

a PC/Laptop/Homeserver/Raspberry Pi/Toaster with enough storage to host everything
Free Software: Sonarr & Radarr & SABnzbd to automatically find movies, shows and download them*
Optional: a free media server like Jellyfin
A Usenet provider. There is a lot of info on this if you look for it but for a beginner I'd recommend frugal Usenet for 40$ a year if he is mostly downloading new stuff:

https://billing.frugalusenet.com/signup/neQeZxl

If he is also downloading a lot of older (think 10+ years) stuff he should get ewaka for 48€/year (or keep an eye out for the 36€ year deal that pops up sometimes):

https://www.eweka.nl/en/landing/special-deal

A Usenet indexer. scenenzbs.com costs 15-20€/year and is THE must have indexer for German content right now. Additionally, Drunkenslug(private, but lot's of invites going around) or nzbgeek (public) are great for english content and also do have some German stuff. They also cost 15-20€/year. To start sceneNZBs should be enough though.

Let me know if you/he needs more info or guides, but like I said it really depends on what his setup is supposed to be in the end

*edit: of course you can also skip Sonarr & Radarr and just search on scenenzbs.com by hand.