Hi.glad you are here!
Besides "Under the Influence", I also have found "Getting Them Sober" full of helpful information (
http://www.GettingThemSober.com has "preview chapters").
Hope you stick around and join us; it has helped me in ALL aspects of my life (not only dealing with the A that got me here!). Chances are that things will get worse for BIL....alcoholism is progressive. (I heard that but didn't really understand until I could think back....after awhile,the idea I had for what I accepted "normal and acceptable behavior" began to shift without my noticing it.......) Reading,being here, AlAnon,etc are all great things....hopefully you will be a beacon leading your SIL to the help that is available,when she is ready to accept it.