You choose which permanent card you're returning to your hand, if any, as Deadly Brew resolves, after permanents are sacrificed.

You cannot return the same permanent card that you sacrificed.

If you cast Deadly Brew and control any creatures or planeswalkers as it resolves, you must sacrifice one of them.

First the active player chooses which creature or planeswalker they'll sacrifice, then each other player in turn order does the same, knowing choices made before their choice. Then all those permanents are sacrificed simultaneously.