Jack Isidore was a tyre regroover by trade, but his true vocation lay in collecting items of amazing information (did you know that the Sargasso Sea actually exists? that the Japanese are not really human beings?) and observing the behaviour of those around him from a detached, 'scientific' viewpoint.
His sister's husband had described Jack as a crap artist, but when he found himself homeless, Fay let him move into their luxury ranch house in Marin County, California. There Jack was able to play with the children-and bring his analytical turn of mind to bear on Fay's strange marriage to foul-mouthed factory owner Charley Hume.
Star Trek The Next Generation