Minecraft server won't let others connect?

I have made a private server for mine craft. I have set it up all the way but when i go to multiplayer i can't see my server, but i can still join by direct connect then typing localhost. Then i can get in but the problem is my brother has a mine craft account as well, so he does direct connect then localhost and gets nothing what seems to be the problem I'm new to this server business please help.

Localhost is the ip of the machine you are using, so if your brother uses other computer where the server isn't installed, then localhost won't connect to anything. The solution, give your brother the IP Address of the computer where the MC server is installed.

Make sure the firewall of the server computer isn't blocking MC.

I'm assuming both computers are in the same network (not on Internet).