Another argument with my brother regarding the wording of cards. 
In Spite’s deck, the Potential Sidekick card reads: “At the start of each hero turn, that player may discard 3 cards. If they do, put this card under the Safe House card. At the start of the villain turn, each player draws 2 cards.”
My reading of this is that if the potential sidekick is saved, everyone draws two cards. My brother read it that as long as the Potential Sidekick card is out, each player draws two cards.
Anyone know how this one works?
Your brother is correct. First part says that on the start of a hero turn, that hero may discard three cards. It then states that if three cards are discarded for this purpose, the Potential Sidekick goes under the Safe House. Once a card is under the Safe House, it loses all game text, and thus drawing two cards is now impossible (the text to allow it is gone). Then, it states that at the start of the villain turn to draw two cards. This can only occur if Potential Sidekick is in play, not in the trash nor under the Safe House.
I agree with your brother.
If a card is in play you read the card text and follow its instructions; the Potential Sidekick is in play, follow the text on the card.
Once the Potential Sidekick goes under the safe house the card text is blank (as per safehouse) and you no longer follow the instructions on the card. The danger is the longer he helps you out the more likely he is to get killed by Spite.
I like leaving him out with other victims as cannon fodder. Especially on hard-mode Spite, the extra cards from him are often worth more than the damage when Spite flips.
In Spite’s deck, the Potential Sidekick card reads: “At the start of each hero turn, that player may discard 3 cards. If they do, put this card under the Safe House card. At the start of the villain turn, each player draws 2 cards.”