Sync an iDevice apps with two Apple IDs
Yes, you can do that. I use two Apple IDs on my iPhone 4S.

It is not the most comfortable setup though: You must switch IDs in Settings>iTunes &amp; App Stores. Just tap on your Apple ID and select Sign Out. Then log in with your brother's Apple ID.

I don't think the iPhone will pull the apps your brother bought when he signs in with his Apple ID. He will have to install them manually.