The other stupid thing about Sporting wanting him to play vs benfica is that Bruno won’t play anywhere close to full throttle and will avoid any tackle or challenge to avoid injury.
His head will be somewhere totally elsewhere so it makes zero sense from anyone’s POV to play that game. And that’s even before one accounts for the financial risk, if he gets injured.
Knowing BF i seriously doubt that, he's the type of player that will give 100% every game and every minute.
If it really is his last game, which i doubt, he will give all he has on the field regardless of consequences.