Shannon,
Antidepressants can be tricky at your mother's age and other health issues. There are a wide range of antidepressants, but it's impossible to recommend one online. This needs to be handled by a physican who has her full medical records. I've dealt with similar situations with my mother's medications and found a psychiatrist with a specialty in geriatric psychiatry to do the best for her. If you need to find a good psychiatrist in your area, her primary care physician may be able to help.
Good luck,
Teri Robert