My mother has been diagnosis with the beginning stages of dementia, has a heart condition ,now she has started falling. What can I do?

Sleeping medications, especially, could be an issue. Try calling her pharmacist and ask him or her to do a side-effect check on ALL of your mom's medications and also look for interactions. Pharmacists are often your best source for medication information, because that's their specialty. Let the pharmacist know that your mother has started falling and that you suspect one of the medications.
Let us know how it goes!
Carol