He was a former child actor who graduated to an Emmy-winning performance as Roman Roy, the filterless, fast-talking middle child scheming to inherit a media empire, in "Succession." Now, the charm of Kieran Culkin is front-and-center, playing a rudderless man-child in the poignant comedy "A Real Pain." He talks with correspondent Mo Rocca about growing into his career; what he learned about fame from the celebrity of his brother, actor Macaulay Culkin; and the surprising thing he dislikes about being a dad.