You can download a trial of ecamm's PhoneView from their site -- and perhaps buy it, I've found it very handy. This will allow you to see everything on your phone, copy photos back and forth, and with Admin mode, get into the works.
You should be able to easily delete Voice Memos, those show up on the opening menu.
You are correct. Basically Apple's approach is a case of Better to be safe than sorry.
What I mean is that music originates from your iTunes library (or Apple Music), so you can afford to lose it if something happens to your iPhone. You still have your music on your Mac or in the cloud. Voice Memos, on the other hand, originate on your iPhone. If something happens to your iPhone, they are gone forever. So Apple has designed iTunes to treat Voice Memos differently, and automatically sync them back to iTunes for safe keeping. This is all based on the fact we're more likely to lose our iPhones (or have them stolen) than we are our Macs.
Unfortunately, this approach has frustrated many users as there is no way to manually override this. Apple did create a Voice Memos playlist to help users better manage/navigate their memos, but there's no way to stop them syncing from your iPhone to iTunes on your computer. The only built-in option is to stop it syncing back the other way.
Getting around your situation
There are really only four options to try and avoid your brother listening to your voice memos. These are as follows:
- Use separate User Accounts on your Mac. That is, use one for you and one for your brother. Each of you will then have your own instance of iTunes. To set up separate user accounts go to System Preferences > Users & Groups and click on the + sign at bottom left. You may need to unlock the padlock before you can make changes. Also, in your login options you may want to turn off Automatic Login. Basically, using this option means you should not share your password with your brother! :)
- Manually delete your Voice Memos from your iTunes Library / Store them somewhere else. The easiest way to access voice memos is to go to the Voice Memos playlist. You can just delete them BUT before you do, you may want to make a copy of the ones you want and store them somewhere else. The easiest way to do this is to right-click on them and select Copy. Then go into the Finder and paste them into a folder somewhere. Once you've done this, delete them from your iTunes playlist. However, this approach does mean needing to keep on top of this for whenever new voice memos are synced from your iPhone to computer.
- Use a different Voice Recording app instead of the built-in iPhone app. There are many out there and many also offer ways to sync and back them up separately from the usual iTunes process.
- No longer share the same computer. A more expensive option, no doubt! :)
You may want to provide feedback to Apple about this also. My personal preference would be that Voice Memos are handled totally outside the Music Library and have it's own designated category and options. Whatever your preference, you may want to send the same feedback for both iTunes and iPhone.
Best Answer
Voice Memos are synced through iTunes.
First you have to turn on music syncing. You don't have to actually sync any music, but that's where the option for Voice Memos is.
When your device is plugged in, click on its icon in iTunes then click on Music on the left-hand sidebar. Check the box next to Sync Music, then ensure Include Voice Memos is also checked.
If you don't want to actually put any music on the device, click the "Selected playlists ..." radio button and then don't check anything in the Playlists, Genres, Artists or Albums areas.
Click on Apply (or Sync) toward the bottom right. Your voice memos will transfer to your computer.
Once on your computer, they'll be in your iTunes Media folder (usually at ~/Music/iTunes/iTunes Media) under Voice Memos. Copy them from that location into a safe place.
Then go back into iTunes, select all on the automatically-created Voice Memos playlist (under Music), and press and hold Option while you right-click and choose Delete. You will be prompted to confirm you want to delete the items, and then to move them to the Trash. I would suggest you do this, since you made a copy of them above.
Sync again and they will be removed from the device as well.