M.R.
Please listen to the post below that urges you to go to Al-Anon immediately. This is not AA, which is for alcoholics -- this is for their family members and you truly need it, now. There is probably a meeting somewhere near you tonight! Surely at least there is one during this week.
They are at www.alanon.org and you can find local meetings online there.
If you're not familiar with it, Al-Anon .helps families cope with alcoholic loved ones and with how those loved ones' alcoholism affects their own lives. There, you will find people who have been through EXACTLY what you are experiencing with your brother, and you can learn so much from their stories. We can't help you the way they can. See if your cousin will go too, but if not-- go yourself. These are people who can truly support you over time, and who can advise you on where to turn next. Please update us and say you've located a meeting for yourself and will go ASAP.