Davina McCall has taken to Instagram to open up about her father's battle with Alzheimer's disease. She shared a photo of her mum and dad alongside one another in honour of World Alzheimer's Day, with a lengthy caption detailing how her family have been coping.SEE: Davina McCall opens up about heartbreaking death of her sisterWATCH: Davina McCall shares her top tips for taking care of you"This is my mum and dad.