When Helen and Casey's mother arrives on Nantucket, Helen isn't sure which sister her mother came to see. And when she finds out her mother gambled away the $10,000 for her and Joe's wedding, she is convinced that Casey has always been the favorite of the family. Meanwhile, Fay and Roy split a ticket to a Barbra Streisand concert, Antonio adopts Deedee as his own mother, and Lowell and Brian stuff themselves on Deedee's food in an attempt to see who can outeat the other.