IPhone. If I turn off Photostream on iCloud will that delete all my pictures?

On my iPone… If I turn of Photostream on iCloud will it delete all my pictures?
I just wanna take icould off so all my pictures don't multiply & get added to iCloud. For some reason my bros photos get saved to my phone & my photos get saved to his. Needa take that off!

I would think that Apple would be the best place to ask

No, they wont. They will be saved to the phone and you can still back them up to your computer or sync it to itunes. They just won't have an auto backup in case your phone gets stolen.