In this chapter, it is only the character who turned the chapter card who cannot use WISDOM. Think of it as all the WISDOM symbols disappearing from their character dice until the end of the chapter. If they roll a WISDOM on their character dice it is considered to be a blank. However, if the affected player rolls a DOUBLE WISDOM, the shield symbol shown on the dice does still apply - they have rolled a blank BLOCK.
All other players can fight as normal, so it falls to those other characters to summon their collective WISDOM in order to survive the combat.
The relic known as Rengorn’s Rune (DCSE-IC11) allows a player to modify their character dice to any result, but since the WISDOM symbols are considered to have vanished from their character dice, the relic is of no use to the player in this chapter.
However, the Distilled Wisdom potion (DCSE-IC07) can be used by the affected player to generate WISDOM in this chapter, since it does not involve the player’s character dice in any way.