I don't know specifically about TC, many programs save customisation settings per user – so if you set up a user account for yourself on the PC, I'd have thought it will not upset your friend's settings. If the licensing is very strictly named user only, a different user account might not be able to run the program (I think that is unlikely).
There may be a 'profile' saved somewhere that holds display customisation etc. – taking a backup of your friend's file before you start changing things would be a good idea as a 'belt and braces' approach.
The TuboCAD user forum might be best place to ask.