These FVC and FEV1 results could indicate a
mixedMixed respiratory vaccine obstructiveAcute bilateral obstructive uropathy
Obstructive uropathy and restrictive lung problem. If your mom has smoked, these results could also indicate pure obstructive lung disease, such as chronic obstructive pulmonary disease (COPD). She needs to have a chest x-ray and additional pulmonary function testing to sort this out.
In either event, your mom does have decreased lung function. However she has enough lung function to live for many years, if not decades. Having a living will is always a good idea. In this instance it’s not because death from lung disease is imminent. Certainly your mom’s doctor knows more about her health than just these results. Perhaps you should get permission from your mom to speak with her doctor. Then you could get the full story from your mom’s doctor directly.