What side are you on? Vecna controls MFlayer VS MFLayer controls Vecna

I still don't know what to choose because of ONE LITTLE SENTENCE. Vecna says to Max in S04 Ep9 "You're braver than your Brother" That to me worsens the question of If the MF controls vecna or Vecna Controls MF because it can go either Way

So what do you choose? Vecna controls MindFlayer or MindFlayer controls Vecna?