The keyword Nocase
defines case-sensitivity for the language which is used by syntax highlighting and by auto correction. It is not possible to configure case-sensitivity for syntax highlighting different to case-sensitivity for auto correction.
What you want is partly possible if the keywords are written either in lower or in upper case, but not mixed or with just first letter in upper case and the other characters in lower case.
Remove from the wordfile from first line Nocase
to make the syntax language case-sensitive. Then create a copy of the lines with the upper case keywords in each color group and convert the keywords in the copy to lower case. The case-sensitive syntax highlighting language contains now the keywords completely in upper case and completely in lower case. On entering a keyword the first character defines the case for the entire word. The keyword is corrected to completely upper case if the first character is in upper case, otherwise corrected to completely lower case. This is not completely what you want, but perhaps nevertheless useful.
Further I suggest to define 2 wordfiles for the language. The first one is case-sensitive with all keywords only in upper case. This wordfile contains File Extensions =
with the appropriate file extensions list to automatically apply this wordfile after opening a file with the associated file extension. The second wordfile is also case-sensitive, but contains the keywords in upper case and in lower case (or is alternatively not case-sensitive. This second wordfile contains just File Extensions =
without any file extension. The language name of the second wordfile should be also slightly different in comparison to language name in first wordfile.
The second wordfile must be manually chosen for an opened file via status bar at bottom of main application window or View as (Highlighting File Type)
which is done when the opened file is an old one with all keywords in lower case.
In case of you ever want to convert the old code from lower to upper case, see Auto correct an existing file