How do I disable sharing on My Mac

Hello everyone! I'm new to the forums, but I've always relied on your answers to help me out when I'm in tough situations, but I can't find the right answer to my question So i thought i'd sign up and ask

My question is as said on the top. Ever since my wifi has stopped working I've been paying my neighbor to use his, although for some reason it says we are 'sharing' , more specifically, right under where it says 'Devices' on the finder it says 'Shared' and I can see his Mac's screen name(or whatever it's called) right under there. He can see it too and thinks I'm trying to hack him. How do I disable this on my computer? or does he have to disable on his Mac?

Again, thanks, I love this website.

This just means you are on the same network. Unless he's specifically allowed access to other parts of his computer, the only thing you could get to without his password is his Public Folder (and vice versa).

Macs. They are secure.