Help App sync?

[blahxblah1005]

I've been given a hand me down Android phone with my brother's stuff still on it.
His google account syncs all his apps and what not. This is a rather silly (probably really dumb) question but I am new to using phones and androids especially...
My question is, if I download an app on his old phone... will it sync to his new phone? Or is that not how it works?

 

[Hadron]

You can install an app to your phone without it installing to his.

But if either of you syncs stuff with the Google account (contacts, calendar, etc) that will end up on both phones since they are syncing with the same account.

 

[Mr. Lucky]

^^^ Yep
Another option might be to do a factory data reset (accessible is Settings) and then start over with your own Google account.