Hey RO,
Ok so interestingly enough I had a friend of mine removed from a position of service over this very issue. I followed it as closely as I could and there are a few things you should know. Your friend most of all however, has to get over his nerves, and not be afraid to ask them questions, and WRITE DOWN the answers. Make sure he asks very directly if this is an investigative comitee, or a judicial hearing.
Here are some key questions;
1) Brothers, you mentioned multiple warnings regarding alcohol, can you please tell me when these occured? (Write down the answers. Get DATES)
2) Brothers who has accused me of being drunk and what is it this person said they saw? (write it down....do not show annoyance but rather concern) You have the right to know the NAMES of your accusers. There must be more than one, and they have to be names. You also have the right to confront them and bring them into a meeting if it progresses. Do not let this one go. People back off when called out to this extent.
3) Brothers is a there a reason you did not tell sister _______ to apply mathew 18 if she was stumbled by something that I did? (let them explain why it doesn't apply, and be sure to then look it up and read it to show it DOES apply)
4) I really need to speak with my accusers to be able to win back my brothers, before I go any further with you guys. I believe there has been a misunderstanding.
Something like that. Don't shy away from your rights.