Zyperspace

I wanted to avoid this, which is why I'm asking the forums for advice. I will do this for now. I find it odd that I've been able to separate the installation and workshop mods until now...

I have limited space on my C: drive SSD, so I offload to my E: drive HDD when I can, and ArmA 3 mods is one of those cases. However, recently I got Library Share with a friend to use some software he owns on Steam, and it started downloading 55GB mods he was subscribed to. Which wouldn't be an issue if it wasn't for the fact that it put it on the C: drive instead of the E: drive, which I specifically marked in the launcher. How do I change this? I can't tell him to unsubscribe, that's ridiculous, I had to uninstall another game or I would run out of space on my C: drive... I just checked in-game and the mods aren't even enabled, guessing I can only use my friends' installed mods when I'm logged in as him? Help would be greatly appreciated, thanks and happy holidays!