My mother has problem sleeping. She tends to forget things quite frequently and often gets confused in otherwise simple discussions. This morning, after a troubled sleep, she woke up and had a major delusion and confused the maid with the milkman. She also complained of dizziness after that. The last year that went by has been particularly difficult for her mentally and emotionally given how my father passed away almost a year ago due heart failure. Are all these symptoms hinting towards a case of Alzheimer's? Or any other serious illness?