Sarah...
I'm sorry to hear about your dad's situation, as well as all that you had to endure those many years. I'm glad that you were able to reach out for some help and guidance.
I've met many alcoholics in my life, some with physical problems on par with what you've described. Many were able to get quite a bit better once they got professional help with getting the alcohol out of their systems. Of course, once the alcohol is out, it's then time for the person to look at the reasons why they willingly did so much damage to themselves (and their loved ones) in the first place, so that positive changes can be made.
The human body has incredible power to recover when it's given the chance. Alcohol is a powerful toxin, as you no doubt now know.
You can find information and support at Al-Anon meetings:
For families and friends of alcoholics