Why is my brother having trouble playing my games while we are game shearing

Well, on my network, I have my Xbox 360, my PC, my brother's PC, my mother's PC, & a back-up drive. We all leave our PCs on. Often times my brother's watching HD movies on his PC while I play my games. It's when he tries to upload files that it kills my
connection. My mother rarely uses her PC & I don't use mine while playing games...

No issue! I game share with my brothers, and when I am on my own Xbox, I can play the same game that they're playing, even without having two copies. Part of why my family's Xbox is set as my home console is so we can do that.

Me and my brother are game sharing but i cant play the games he bought online why is this?

In order to share his games he would need to set his account as Home on the console you're playing on or you would need to have his account signed in while you play.

Have you tried changing any of the game setting?

I've had that problem once while playing split screen with my brother and we noticed that changing some of the game settings helped with our problem.

Hopefully this helps your situation.

Sight being one of the few senses we use while gaming I can see why they'd say having a clearer picture would allow you to play better. The whole thing with your brother is anecdotal anyway.