Jay Leno shared a touching moment with his wife amid her battle with dementia. RadarOnline.com can reveal the comedian and former late night host was seen holding hands with Mavis Leno, who was diagnosed with “advanced dementia”. In the rare sighting of the couple – who have been married for 44 years – Jay, 74, was spotted hand-in-hand with Mavis, 77, as they left a comedy show. Jay was dressed in a navy blue suit and patterned white button-down. His beloved wife wore a floral blouse, blank pants and blue sneakers. He tightly gripped her hand as they left the stand-up show in Los Angeles, Cali…