"I mean you shouldn't be downloading illegal things but they shouldnt be watching what you download either. "

Again...Right from the EULA that he (or his mom) agreed to by paying the monthly bill:

"CoxCom, Inc. and its local affiliates and/or distribution partners (collectively "Cox") are pleased that you have chosen Cox® High Speed InternetSM service (the "Service"). Our goal is to provide you with an enriched, high-quality Internet experience. This Acceptable Use Policy (the "AUP") has been designed to protect our Service, our subscribers, and the Internet community, from inappropriate, illegal or otherwise objectionable activities. Please read this policy prior to accessing the Service. All users of the Service must abide by this AUP. Your violation of this AUP may result in the immediate suspension or termination of either your access to the Service and/or your Cox account. This AUP should be read in conjunction with our Internet Subscriber Agreement, Privacy Policy, and other applicable policies.

By using the Service, you agree to abide by, and require others using the Service via your account to abide by the terms of this AUP. You should consult this document regularly to ensure that your activities conform to the most recent version. IF YOU DO NOT AGREE TO BE BOUND BY THESE TERMS, YOU SHOULD IMMEDIATELY STOP THE USE OF THE SERVICES AND NOTIFY THE COX CUSTOMER SERVICE DEPARTMENT SO THAT YOUR ACCOUNT MAY BE CLOSED."

Don't like it? You have three choices:
1. Have your mom cancel Cox to stick it to the man
2. Stop downloading illegal stuff you know is illegal to do.
3. Bitch about it on the internet

Cox, Comcast, Verizon, and every other cable/telco company has packet sniffers and network monitoring tools set up and running 24/7 to weed out illegal activities. It's no different than your work monitoring your internet traffic while you are at work (which they all do also).

They did that to me over a copy of Leisure Suit Larry (the first one... from 1987) I downloaded... and promptly played stupid and blamed on my brother.

charter internet sucks too

I'm pretty damn sure they're supposed to ask your permission before doing something like that...
Broadband don't care about downloading :D