How do Marie and Daniel get Katie to see Matt's life in a different light?

Marie tells Katie that Matt is happy in his life, in his choices, and it is only Katie who is disappointed in him. Katie becomes angry. When Katie tells Daniel what Marie has said, he agrees with Marie, causing Katie to become enraged. However, as the party begins, Katie finds herself really seeing Matt for the first time in years. Katie realizes that Matt is living the life he wanted and just in a different way than he had intended originally.