from https://productforums.google.com/forum/#!topic/webmasters/XTmiHxe-VsI
Log into the google+ account, select the "Home" drop down in the upper
left hand corner. Select "settings", Scroll down to about half way
down and select "Manage apps and activities", Select the edit (pencil)
tool for clash of clans and select "disconnect". Make sure you check
the box that asks about erasing all activities for this App. It takes
about an hour for Google to erase all data for the app, but after that
you can then re-connect with the account you want to use.
and another one http://cocland.com/tutorials/removing-clash-of-clans-from-google-account
This was not an easy thing to track down via Google or even clicking through my Google+ account menus. Hopefully this may help others.
Did you actually link your clan to his Google+ account (by going to settings)? It's not done automatically, and only one village can be linked to a Google+ account. If your brother later linked his village to the same Google+ account, then your village will no longer be linked to it.
The only way to get your existing village back is if it's still on your brother's Android device. If you still have access to it, you can link it to your own Google+ account or use the "Link a device" option in the settings to get it onto your own phone.
If you don't have access to the village anymore, and using the Google+ account that it was supposedly linked to doesn't load your village, then the only way to get it back is to contact Supercell directly.
You can submit a help request by sending a message from the game on your device. To send an in-game message, tap the in-game settings icon, select "Help and Feedback", and then tap "Report an Issue". That will assure we have all the necessary data to make the recovering process as quick as possible.
Please include the following information in the message, so that we can locate your village:
- Exact name of the two villages
- Exact level of the two villages
- Exact Town Hall level of the two villages
- Exact clan name of the two villages
Please note that the information is required for both the lost village, and the village that you currently have on your device.
I would recommend doing this from you brother's phone as the device information will help them locate the lost village more easily.
If for some reason you can't use the "Report an Issue" option, there's also the option to send an email to clashofclans.android@supercell.net, though it is generally recommended to use the first method if available.
Best Answer
The "link a device" option enables you to play your village on multiple devices but importantly with different operating systems. For example an Apple iOS device and an Android device. Without the "link a device" option cross platform accounts would not be possible.
Here is a good Guide in the wiki on linking devices