Lisa Rinna took a trip down memory lane while mourning the loss of Patrick Muldoon following his death on Sunday, April 19. Rinna, 62, shared a throwback photo from their Days of Our Lives era via her Instagram Story on Monday, April 20, as tribute to Muldoon, who suffered a fatal heart attack at the age of 57. She added a broken-heart emoji to signify his tragic death after the pair played sister and brother on the soap opera in the early 1990s. Lisa Rinna, Patrick Muldoon.