As per the age of your mother and the description of symptoms you gave about her, its possible that your mother is developing Dementia, which causes forgetfulness in people and difficulty in recalling things. However a proper and thorough assessment of the same is required before confirming the diagnosis. Its important to assess if she has any other symptoms as well, like difficulty in sleeping, seeing or hearing things etc.
Next Steps
Early intervention is the key to stopping dementia from further progressing and worsening, as medications given at the initial phase can help stop the illness. A radiological scan of the head may also be required.
Health Tips
Is your mother suffering from hypertension? If yes then please keep a watch on her Blood pressure, as forgetfulness can also be seen in stroke.