As part of Brewster's shopping spree, he purchases a rare "inverted Jenny" stamp for 1.25 million dollars, the highest price ever paid for a stamp. Cut to his rivals' office, reading about it in the paper and laughing that he's violated the terms of the will by acquiring an asset. One of them picks a postcard and reads, "Gentlemen, having a wonderful time, wish you were here. Monty Brewster". He then sees the stamp that Brewster used to mail the postcard...
When learned about the scheme to defraud Brewster from his inheritance, he punched one of the lawyers involved with the scheme and completed the fulfillment of the condition by paying the fees of another lawyer to defend him from the subsequent assault lawsuit.
When Angela was about to slap Warren for his role in the plot to steal the inheritance, Monty stopped her, claiming she's a lady and he wants her to stay as such. As Warren was complimenting Monty for the advice, Monty punched Warren.