that mean you are using public IP,
for your brother to be able to connect to your server you need to configure this:
1. setting port forwarding on your router, set port fort forwarding for port Launcher (80, 8080, 10007), Login Server (10001), zone server (27780), port forwarding setting depend entirely on your router product (it could be called NAT, or port forwarding), call your ISP for help or try yourself
2. set ALL *.ini setting in account, login and zone server to 127.0.0.1
except WorldInfo.ini
3. open WorldInfo.ini and add GateIP = (your public IP from whatismyipaddress.com) so it become:
[System]
GateIP = xxx.xxx.xxx.xxx
4. set your launcher IP and emulator IP to your public IP from whatismyipaddress.com
5. open your server and restart your apache,
to test whether you could connect or not, open this site :
https://www.yougetsignal.com/tools/open-ports/
put your public IP into remote address, and port number 80 and then click check, try next port 8080, 10007, etc
if it says close, then you failed on setting port forwarding setting, if it says open, then you could connect,
note: you have to open the server and the apache before checking your port open, if you didn't open the server application, it will always say closed