The 85-year-old actress's ill-stricken former co-star, who played her character Dot's on-screen husband Jim Branning, suffered a stroke in 2007 which has left him unable to walk or speak fluently.
When Brown asks her former colleague how his condition makes him feel, 73-year-old Bardon can only respond by whispering: "Oh dear."
Bardon's wife Edna says of Bardon's current state: "He's going the wrong way now. His main pleasure in life is when his grandson Harry visits."
Brown said of her rapport with the actor: "We got on very well. We got to understand each other. We could give each other notes without offence.
"We had a very good rapport and good timing. We laughed a lot, which is nice. It's the best way."
Brown, currently on a six-month hiatus from EastEnders, last week revealed that she visits Bardon "regularly".
Brown's documentary Respect My Elders airs this Thursday (July 12) on BBC One at 10.35pm.
