The issue is the en-US. This indicates that the system locale has English as the language, and US as the country. The Africa/Nairobi part is the timezone.

The way to get KES to display is by setting the language and country to a Kenyan locale that supports them. The following are all supported* Kenyan locales in Java 8:

Display Name     Code   Sample
-------------------------------
Somali (Kenya)   so-KE  Ksh1.00
Kamba (Kenya)    kam-KE Ksh1.00
Oromo (Kenya)    om-KE  Ksh1.00
Luyia (Kenya)    luy-KE KES1.00
Kikuyu (Kenya)   ki-KE  Ksh1.00
Meru (Kenya)     mer-KE Ksh1.00
Embu (Kenya)     ebu-KE Ksh1.00
Teso (Kenya)     teo-KE Ksh1.00
Luo (Kenya)      luo-KE 1.00KES
Samburu (Kenya)  saq-KE Ksh1.00
Kalenjin (Kenya) kln-KE Ksh1.00
Gusii (Kenya)    guz-KE Ksh1.00
Swahili (Kenya)  sw-KE  Ksh1.00
Taita (Kenya)    dav-KE Ksh1.00
Masai (Kenya)    mas-KE Ksh1.00

If you don't want to set your system locale to one of these, you can pass them as system variables to Java. For Tomcat, this means changing the CATALINA_OPTS variable e.g.:

CATALINA_OPTS=-Duser.language=so -Duser.country=KE

If you are running the standard Tomcat scripts, this can be done by setting the CATALINA_OPTS environment variable:

Windows
In a setenv.bat script in the same directory as catalina.bat, add:

set CATALINA_OPTS=-Duser.language=so -Duser.country=KE

Unix
In a setenv.sh script in the same directory as catalina.sh, add:

export CATALINA_OPTS=-Duser.language=so -Duser.country=KE

If you are running Tomcat as a service on Windows, the setenv.bat script is ignored. You will need to consult https://tomcat.apache.org/tomcat-7.0-doc/windows-service-howto.html for instructions on setting the JvmOptions parameter.

* Locales were listed using the following code:

public class KenyanLocales {

    public static void main(String[] args) {
        System.setProperty("java.locale.providers", "COMPAT,CLDR");
        System.out.println("Available locales: " + Locale.getAvailableLocales().length);
        System.out.println("Kenyan locales:");
        System.out.printf("%-16s %-6s %s\n", "Display Name", "Code", "Sample");
        System.out.println("-------------------------------");
        for (Locale locale : Locale.getAvailableLocales()) {
            if (locale.getCountry().equals("KE")) {
                System.out.printf("%-16s %-6s %s\n", locale.getDisplayName(),
                                  locale.getLanguage() + "-" + locale.getCountry(),
                                  NumberFormat.getCurrencyInstance(locale).format(1));
            }
        }
    }
}

If you are running Tomcat as a Windows service, then the catalina.bat and setenv.bat scripts aren't used. You need to configure the service with the changes you put in setenv.bat, using Tomcat8w.

1. Run Tomcat8w.exe, which is located in the Tomcat bin directory

2. Go to the Java tab

3. In the Java Options field, append the properties you added to setenv.bat, one property per line e.g.:

-Dcatalina.home=C:\Program Files\Apache Software Foundation\Tomcat 8.5
-Dcatalina.base=C:\Program Files\Apache Software Foundation\Tomcat 8.5
-Djava.io.tmpdir=C:\Program Files\Apache Software Foundation\Tomcat 8.5\temp
-Djava.util.logging.manager=org.apache.juli.ClassLoaderLogManager
-Djava.util.logging.config.file=C:\Program Files\Apache Software Foundation\Tomcat 8.5\conf\logging.properties
-Duser.language=sw
-Duser.country=KE

4. Click Apply

5. Restart the service on the General tab