premiering April 16 on Amazon, has some funny moments while sometimes veering into a live-action, sophomoric take on dim-bulb pals “Beavis and Butt-Head.” Younger brother Brian takes the lead here as 32-year-old man-child Frank Marron, who’s still living at home in suburban Dublin with his randy mother, Mary (Pom Boyd), who’s both critical of, and in sync with, her son’s temperament and sense of humor.