The helpfile which contains the texts about menu entries is 'help_eng.spi'. The helpfiles about objects are 'option.help', 'passive.help' and so on.
The syntax of the help entries in file 'help_eng.spi' is very simple, so, if you want to improve the text, you can do that using a simple ascii editor. If you would like, you can send us a version of your improved online help text, so other SPICECAD users can benefit from your work. Contributions here could motivate us to implement enhancements which you would like to see.
All help files need to be placed into the directory $SPICECAD_HELPDIR, where SPICECAD_HELPDIR is an environment variable you need to define before starting SPICECAD.