Purchased content (whole games, DLC, etc.) is tied to two things:
- The Xbox Live account that purchased it.
- The original console it was downloaded to.
As such:
- The purchasing account can access the content on any console it signs in on.
- Any account can access the content on the original console.
I have no idea though about Child Accounts or parental controls. I found a few links that may help:
http://support.xbox.com/en-GB/xbox-3...tal-safeguards
http://support.xbox.com/en-GB/xbox-3...rental-control
http://support.xbox.com/en-GB/my-acc...ive-pass-codes