It is as simple as creating a new ID on his iPad. That's all you have to do. That has nothing to with your ID. In fact, you cannot delete an Apple ID from iTunes, because all paid content is always tied to that ID.
Now where there will be an issues is if he wants to update the apps that you bought with the shared ID he must use that ID to update those apps. That in and of itself is not a big deal, but if he creates a new ID and uses that to download content and then does back to the old ID in order to download past purchases - he will lock himself out of the his new ID for 90 days. You can read about that here.