Is COX Internet capped?

[J.]

I moved with my brother for two weeks and he has COX Internet. I use his Wi-Fi and watch a lot of HD videos on Youtube and Netflix. I asked him if his Internet is capped because I don't want him to pay extra money if I watch too much HD videos. He said that he did not know (he uses the Internet mostly for Facebook only).

That's my question, Is COX Internet capped? If it helps, it is 5mbps via cable Internet.