He's not leaving the forums at all. He's visiting a friend, and Badspot will most likely not ban him for just visiting a relative for a small while. If people don't agree with me, then I'll tell you what I would do if I was Mage in this situation.
1. Set my personal text or signature to something like "Visiting brother for the day, see you tommorow".
2. Log out.
3. Visit brother.
1 Day. You needed to notify everyone for a day?
We here at Blockland Forums appreciate Mage very much, and we feel this is not ridiculous.