"lack of communication"

My 86 year old mother bless her was admitted to Warwick hospital from a nursing home I managed to get to the hospital the next day . she was admitted to swan ward she was in a room of her own and basically dosed up with medication and I could not ask anyone anything due to staff to busy . the next day I visited my mother was sat up having another needle inserted into her hand I was told the other one had to come out due to infection .I managed to speak to a doctor who was caring for my mother who advised me that she was very dehydrated and decided on another nursing home which I had arranged near where I lived cut the story short my mothers condition started to get worse and a doctor had found a growth in her bowel so why did Warwick hospital not find this ? Sadly on the 15th July 2014 she passed away I still feel anger and still cannot understand why this hospital did not find this . I would of been more prepared for the worst and not the shock of a doctor telling me.