How to play Minecraft without host?

Me and my little brother used to play LAN where I’m the host, meaning I created our world.

But the problem is that my brother has to wait until I login so he can play, but now he wants to be able play even when I’m not at home.

So, I know I’m talking about a private server, but a I don’t to want buy one. Is there a way to do that? Some kind of “free” server?

I have no intention of making money from it, so I don’t care if is an “only LAN” solution. In conclusion, me and my brother want to play on the same word without needing some of us to be a host.

Also I wouldn’t want my PC up and running 24/7.