This is So Sad

Don't do that! That's still account sharing and thus breaks the ToS!

*ahem* Now that that's out of the way: I feel like this is a great opportunity to teach your brother about respecting other peoples' things, and being careful with things that are shared with you. If you still have enough trust in your brother, I recommend just showing him your disappointment and see what he's willing to do on his own.

I once got my brother's main Diablo 2 character killed, when I was mad at him... He didn't even have to ask me for anything, once my head cleared I regretted it so much, that I tried to regain all the XP he lost. Aaaaand got him killed another time, this time due to incompetence. Still, the gesture was enough to make my brother forgive me.

Still have passwords for quite a few of his accounts, and if his memory wasn't as horrible, he'd still have plenty of mine. Honestly, if both parties handle it right, breach of trust can be an incredible opportunity to make that trust even stronger than before.

But as said, obviously you shouldn't do it, because the ToS disallows it. ;)

We shared each other account