Backed up 2 iphones on one cpu?

So i let ripped some cds for my brother and put them on his iphone. In order to do this I connected his phone to my itunes. His phone backed up as soon as I put it in. I manually synced his music and thats it. Our iphones have different names. After I was done I forgot to check his phone to make sure get didn't get any of my contact notes or photos.

Since his iphone backed up on my cpu is it possible that our phones have the same information as far as notes, contacts and text messages (not worried about music).

Will our iphone back ups be fused into one backup pr in other words become corrupted because the backups are for two different phones? If for some random reason he needed to restore his iphone from my itunes will he end up getting my information too? Is there anyway to see what backups are in my itunes.

I have a lot of passwords in my notes app and I really hope he didn't get my notes because I know he wouldnt tell me and he would login into my emails, bank accounts etc.

ITunes can definitely distinguish between 2 different backups. To see the backups you can go to iTunes > Preferences > Devices and it will show them all. If your brother wanted to restore his phone on your computer that would alsobe possible.iTunes would ask you once it restored the phone whether you wanted to treat it as a new phone or it would give you a choice of backups to restore from and you could chose his iPhone back up rather than yours.

It is very unlikely your information went onto his phone. You would have had to specify that you wanted to sync your contacts, notes or photos. Your text messages etc. Would not sync from your computer.