Your husband was probably thinking of you when he made his living will. He knew what he wanted. He didn't want you (or anyone else) to have to make that decision. You may feel sad, but don't feel guilty. We don't get a choice about coming into this world, but some get a choice of how to leave it. Death is so personal. I am only beginning to understand these things as my best friend loses her own battle with ESLD from cirrhosis and Hep C.
Your love and compassion for your brother is beautiful. Do what makes you comfortable. I still get cigarettes for my girlfriend even though I know she shouldn't be smoking. I can't make the call for you on getting alcohol for your brother, but you will do what you can live with.
My friend stopped drinking 6 months after her diagnosis and has actually told me that she was greatful for this disease because it got her to stop drinking. She had been trying for over 30 years with no success. It sounds odd, I know, but once I thought about what she was saying and how hard it has been for her all these years knowing that she needed to quit but couldn't, I understood. Alcohol gets a hold on people just like any other addictive substance. Since it's legal and sold in grocery stores, etc. it seems like it's ok. Knowing what I know now, I am so glad I gave it up 30 years ago.
You try to hang in there. This stuff is hard, but coming to the forum and reading helps me. I hope it helps you too. All of us are going through something similar and it's comforting to me to read others' posts to know that I am not alone. Now you are not alone either!
Best friend is in ESLD, has HepC and cirrhosis.