I think its compared to cancer because they share a lot of things. Both are complex disease, require specialized care, may not respond to treatment, and if they do it can reoccur, once you have it your at higher risk for it coming back even if you do all the right things. A person who recovers from cancer might exercise, eat better, get checkups, but it could come back. A person who goes in to recovery can do all the right things and work whatever program they want, but it wont make them a superhero, things can always happen to trigger them and they can relapse even if they don't want to. I could think about it like a tumor in the brain. It starts out small and I dont notice anything happening, then it gets larger and maybe some of my family thinks something is wrong with me but I feel ok, they say this coke I take might be to blame but there is nothing wrong with me that I can see, then I start making some mistakes, people are getting angry, and they keep saying the coke it to blame, but it is the only thing that makes me feel better and I dont understand why they cant see that, I try to go to work and make good decisions but they end up not working out, they sounded good at the time and now I think maybe something is wrong with me, but it cant be the coke because it makes me feel better without it I feel sick, depressed, like I will die. The addiction tumor gets bigger and bigger and now my brain isn't working right but I'm not sure what is going on all I know is I feel worse if I don't have the coke and I think my family is crazy because they think it is causing my problems so I lie to keep them from knowing, or being angry. Until one day I get so sick I end up going off with a friend of a friend who is a dealer, and I hang out there not realizing I'm very sick, even throwing up blood I don't know why. None of it makes sense until I wake up in the hospital after two weeks, part detoxed and now maybe I think they could be right it was the coke, but I think maybe I can quit on my own .
A lot of this comes from my husband. He is in rehab now. I hope one day your sister gets help, my husband almost died of this disease.