You're confusing a few things here – as mentioned – but there's a bit more to it.
The Elder Scrolls III: Morrowind is a classic RPG 15 years old now, which had two expansions called Bloodmoon and Tribunal.
The Elder Scrolls Online is a MMORPG originally launched in 2014 for PC/Mac and 2015 for consoles. It's a buy to play game with no forced subscription (other than being a member of PlayStation Plus or Xbox Gold respectively). You can start an optional subscription for full access to all DLC (and other benefits), but it's up to you. As an alternative you can buy DLC as you're used to for games such as Skyrim.
The Elder Scrolls Online: Morrowind is a so-called chapter (basically an expansion pack) released earlier this year, which expands the game world with the Island of Vvardenfell (same location as TES3, just 700 years earlier).
The 59$ retail (or online) version you've bought is basically the "full package": Your friend gets both The Elder Scrolls Online: Tamriel Unlimited and The Elder Scrolls Online: Morrowind. (Existing players can get a 40$ discounted "Upgrade".)
The whole game world scales with your character so your friend can experience the whole game – both the "old" regions on mainland Tamriels as well as Vvardenfell – right off the get go. There is no "aimed at high level players" except some "Veteran" geared content (like higher difficulty versions of Trials; ESO's equivalent of raids).