A psychologist could do sensitive testing to clarify the extent of her memory problems and what the likely cause is. Generally, with most forms of memory problem, its short-term and recent memory that suffers first, and long-term memory that lasts longer. It'd also be worthwhile helping her to get a full medical checkup, as there can be a range of causes of memory problems such as depression, vitamin deficiencies, thyroid problems, and so on, which can cause major problems but are usually rather easily treated.