Could Extreme Mood Swings While Having Mild Dementia Indicate Progression Of The Same?

Hi thankyou. My mum was diagnosed with mild dementia in may 2013. she has been in a nursing home since then. She knows who I am, who she is etc. She s beginning to lose interest in activities at the nursing home. She s very teary and wishes she could go back to her old life, but when I talk to her about the old life she is glad she isn t in the family home as she knows she couldn t look after it. My question is.... is my mum falling victim to the later stages of dementia? and what else can I expect to happen with her...thankyou jackie