Sure you can. In fact, Creative Cloud has the last 7 versions going all the way back to CS6 (12.02). So install as many as you need. Just don't launch more than one at a time.
CS6, if it's the older, perpetual license/disk version, has been known to have issues starting up once the CC has been installed. CC also comes with CS6 though, which is likely why the old perpetual license one will occasionally get confused.
Personally I have CC2015 and CC2019 installed currently (had CC2018 in there too at one point).
In the Adobe Creative Cloud App > Dreamweaver > Manage > Other Versions
If you already have Dreamweaver CS6 installed and what to install the latest version in addition make sure the 'remove older versions' checkbox is unchecked
Thank you all.