I don't let my brother setup a net-server either...
I have my reasons behind this, mainly is that I don't want to try and check a page on MSDN and have to wait 6years for some retard to stop surfing my brothers site just so I can view the page.
Terminal / Optical Cable lines, are the only *real* viable method of hosting a Server. Simply because they are designed for upto 65K Connections at once. Cable modems are usually design for upto 16max, my NTL one will only handle 3 Download, 3 Upload Streams; but because I have all operations routed through a single server, this means every computer on my network uses the same Upload/Download stream... games also will route multiple connections through a single stream.
In this fashion Games networking methods allow as many people as your connection speed will allow.
However, that isn't how Web Servers work; they use multiple access points; in order to prevent data overlapping and people hacking other people (IPVSec6). It is for everyone elses safety; as such standard home connections are not designed for that amount of streams. Furthermore alot of them although they don't have a limit on data overall bandwidth, they DO almost certainly have a limit on throughput bandwidth (the calls and recieved for connections).
Also as most will *not* have network task queing, (which believe me is a pain in the ass waiting for someone elses page to load before yours does, hense why i changed the network setup here) it will mean that anyone additional trying to reach your host will simply get a 505, too many network connections.
Really if you want to do this stuff, then you should talk to your brother about why he won't let you, and also discuss with him possible solutions you could have.
At the end of the day, web-servers are the most demanding things you can put on a computer network wise. game-servers are the most demanding things you can put on a computer resource wise.
Also unless you happen to understand networking fully, you will not be able to fixx problems that could arrise (suchas renewable IPs, as most Static Cable IPs are DHCP leased, for 2-12months)