Nah. the Paul brothers know and understand the business. They know that Manny Pacquiao can still fight dangerously.
They won't risks challenging him as that will result in their 1st loss.
But since it's an exhibition, maybe there will be some script but I doubt Manny will follow the terms about allowing them to win.
Most of the exhibition fight are doesn't have any judges, so in order to win one of them need to knock out their opponent. I think Manny will accept to fight like this rule, if both of them can't knock out their opponent, the fight will not scored, it's not a draw too. This will become a win-win situation for both of them, also it's not possible for Manny Pacquiao fight with Jake Paul on the professional record. Pacquiao is currently at Welterweight division which is 147 pounds while Jake Paul is currently at Light heavyweight division which is 175 pounds.