Brief Answer:
Consider other conditions listed below

Detailed Answer:
Hello and welcome.

Thank you for writing to us.

I can understand why doctor's would first suspect diabetes, given her age; but you should know that dryness of mouth can be a symptom of many other conditions, and not just diabetes. Let me list the conditions for you so you can discuss them with her doctor, and find the exact cause for such a presentation. They are:
-Dehydration (check on hydration levels and symptoms of dehydration)
-Thyroid abnormalities (thyroid profile)
-Sjogren's syndrome (antibodies common in Sjogren's syndrome)
-Kidney conditions (require a renal function test)
-Sarcoidosis (chest x-ray or CT scan)
-Stomach infections that can lead to dehydration
-Poisoning (eg. iron, aspirin, etc.)
-Dry mouth syndrome (check on salivary gland function)
-Abnormalities of salivary gland (require CT or ultrasound of the region)

Please request for the tests mentioned in the brackets for a more clear diagnosis and to help find the exact cause.

As for the pain described by your mother, this can be related to the presence of an ulcer, as ulcers often mimic symptoms of a cardiac condition; but taking her age into consideration it would also be wise to request for an EKG (ECG) to rule out any cardiovascular abnormalities.

I hope you found my response helpful. Please feel free to write back to me for any further clarifications, I would be more than happy to help.

Wishing your mother a long, beautiful and healthy life ahead.

Best wishes.

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