Help! Multiple steam account using same/different mods!

[Snowfoxrb]

I need a little help here. I and my brother share the same computer, and we play DST too but in different accounts. The problem is some mods I play normal before he log in, but after he's log out, I must download that mod again ( already subscribe in steam) and steam doesn't download itself. I must unsubscribe and then subscribe again to make it download. It take time and some mod like Touhou music mod is really large to download all over again. Anyone can help me to share mod for multiple account or at least backup that mod for another user?

Thank you very much for helping me.