Refusal to pay out life cover

My dad had a life cover with them and when he passed away they refused to pay out his cover because they said he was depressed and an alcoholic. This had nothing to do why he passed away. He did not die of alcohol poisoning or he did not try to commit suicide. He was sick and was in hospital for over a week. As long as you pay the premium every month on time that is all they care about. It shouldn't matter what lifestyle you choose to live. If you pay your premiums that is all that should matter. This is a ************** against alcoholics and people who suffer from depression. Aren't they also aloud to be covered?They say that they will take care of your family after you are gone but that is a lie and then you are not here to fight them. Me and my family all had policy's with them but have now cancelled them as we are not rest assured that our families will be taken care of after we are gone.