I'm so sorry about your friend.
Benzos are very dangerous to mix with excessive alcohol use, though plenty of people can drink small amounts like a glass of wine on them and be fine (my gf takes clonazepam and drinks and sometimes even gets drunk occasionally with no problems); your friend was just really, really unlucky.
A lot of people think it's weird that I refuse to drink AT ALL, but between my medication, severe emetophobia and a strong predisposition towards alcoholism with a history of serious mental illness, it's just not worth it for me to drink. There's totally nothing missing from my life without drinking; I can still go out with friends who do drink and it's a total nonissue. (I hate bars and clubs because I hate noise/not being able to talk to people, so I don't really do that anyway, but when I do and don't drink, no one cares.) So if the thought of drinking any alcohol on the medication causes you that much distress, you can always give it up.
But you're not going to die just from taking the medication as directed.