the help system can only work with ar-JO or ar-SA it does not work when the culture is less specific like ar, it will fall back to English if it does not see the files and it will not see the files with just ar
using this does work for me:
<add key="UseCultureOverride" value="true" />
<add key="site1culture" value="ar-JO" />
<add key="site1uiculture" value="ar-JO" />
with help files named like ar-JO-helpkey.config
resource files may fallback to ar if ar-JO is set as the culture and no ar-JO resx files exist, but the help file system is not smart enough to know that ar is a suitable fallback if ar-JO files are not found