Android - Can I share my Google Play "cloud" music with a family member?

Any music you purchase via Google Play Store or upload via Google Music Manager application is tied to whichever Google account you selected within the app under Menu -> Settings -> Google Play account. Starting with Android 2.2 (a.k.a. Froyo) you can add multiple Google accounts on Android devices (phones, tablets, Google TVs, etc.) Therefore if your relatives' handset/tablet supports multiple Google accounts, you can add your own account under Settings -> Accounts & sync on their device, and then within their Play Music app's settings you should be able to change the account to yours. The music should then be available on their device to stream/download.

Using the Google music uploader tool, you can also download all (Purchased only, I believe) music from any given Google Play Music account. You could then switch accounts (or better yet, a different computer), and upload that music to a different Google Music account.

It would be a manual sync process, as the uploader tool won't automatically download purchased songs.