Unfortunately, a close member of my family suffers from alcoholism. 
I'm sorry to hear that. Alcohol usually affects the brain, heart, liver, pancreas, and immune system more than other parts of the body. Does your family member have any problems due to alcohol?
Yes, I think her liver is starting to show the effects. She's been drinking long term- over 20 years. 
That's really unfortunate. Its even more unfortunate that if she doesn't stop the alcohol is capable of damaging all the organs in her body
I know. She's tried to stop drinking but can't seem to do it. I'd like her to go to rehab but she is unwilling at this point. 
Well, at the end of the day theres nothing anyone can do unless that person themselves wants the help :\
That's right. I think it's up to her to decide when it's time. It can be hard to live with though!
The risk of cancer, irregular heartbeat, cirrhosis of the live, and all the other problems it can cause are enough to scare me away
I like a drink but I seem to know when to stop, I wonder what's different with an alcoholic?
Its when other factors come into play. Such as not being able to limit, Or when the withdrawal symptoms happen quite a bit