Actually, alcohol can hinder sleep in a few different ways. First, it is shown to reduce your REM sleep. This stage of sleep has been shown to be very important in brain function. Simply, we need to get REM sleep or else we harm our central computer; the brain!
Second, it may cause you to dream. This is not necessarily bad, however, some of these dreams may be nightmares. Sometimes, whether you know it or not, this may cause you to thrash around and/or disrupt breathing, thereby disturbing your normal sleep.
Last, it may cause inflammation in the nasal passageways. This in turn reduces the amount of oxygen getting into your body. The body, and more specifically brain, need oxygen to work.
So try to end you drinking a couple hours before bed and you shouldn’t have any problems.