Can you split an account?

My brother and I shared a WoW account for a while but now we’re wanting to get our own. I read that you can get multiple WoW accounts on the same Battle.net account, and play both at the same time, is that still true?

I wouldn’t want to kick him off the account if it means he’d lose his characters/toys/mounts, but I saw a thing in the store to swap characters to another account?

EDIT: I know account sharing is technically against TOS, I think, but that’s why I wanted to make a separate WoW account so we aren’t sharing an account anymore, just having the one battle net. We were both kids when we first made the WoW/battle net accounts. Is there a way to have multiple WoW accounts on a single battle net account