App for a remote control

Hi Forum,

How is one able to use the Cox app for the remote control on their phone, and have it control my tv? A friend was over to my house, my remote wasn't working, I stepped out of the room for a few minutes, when I came back he was using his android phone as a remote controller to change the channels on my tv!  He said it is a Cox app. that allows him to do so. I asked him if he could also tell what programs we had been watching. He said No, but I felt like he tapped my tv. How is he able to do this with an app on his phone? He has no access to my Cox account.  

Thanks!