What level is this homebrew Comatose spell?

I have converted a pathfinder side quest to D&D 5E and given my players a journal with a few spells in it. One of the spells is this:

Comatose: Target PC (or random if not targeted) must make a DC 18 Fortitude save or fall comatose for 1d6 days. A restoration spell is required to wake the PC any earlier than that.

I attempted to bring this inline with the D&D 5E system by changing the following aspects (highlighted)

Comatose: Target any creature (or random if not targeted) must make a DC 13 Constitution save or fall unconscious for 1d6 days. A restoration spell is required to wake the PC any earlier than that.

There doesn’t currently seem to be any casting restrictions on using the spells in this book, and to date I have ruled any PC can cast the spells as long as they know the secret command words which they unlocked during a quest.

However, it feels a little…. dangerous. I don’t like the following about this situation:

  1. There is no “down time” on use of the spell.
  2. It can be cast by anyone, even without proper magic.
  3. I allowed them to target all creatures with these spells, maybe it should be just PCs.

My question is this:

What level would this spell be when compared to other spells in D&D?