My high school was never like that. Always thought that that was more of a TV/movie trope than real life.

Kids are jerks. Bottom line. I've seen the dorks do the bullying as well. So many injured egos running around trying to make themselves feel better. I think most of us on this site can relate and there are no easy solutions. Every bully is different. The sad part is that the solution/problem is probably somewhere at home. Either they're being picked on themselves or are being encouraged by the bullying behavior of a parent, uncle, role model that they respect.

My advice....tell them to hunker down and get through high school. Most bullies don't continue their education and if they do they quickly realize that it won't get them any friends in college. Fighting with a bully whether physically or verbally usually won't get them anywhere; the bully has much more practice and natural skill in this department.

He needs to interject dominance either through threats or returning the mental bullying. If people who are bullied don't stand up for themselves it will plague them throughout their lives. What is happening to him now will seem like nothing when the bullying transfers into his lovelife or work relationships later on etc. Have to stand up for yourself. I know people who have been bullied and let it continue and have permanent mental problems as adults because of it.

P.S.  Nowadays everyone is so concerned with being politically correct and not upsetting anyone ever.  There is absolutley nothing wrong with having 1 good fist fight to stop people from screwing with you.  Absolutley zero wrong with it.  There are people who do not understand reason.  This becomes much more apparent as you become older say above mid twenties and onward.  You don't even need to win.  Simply standing up for yourself will stop people from targeting you.

So.. Nobody asked for a picture of the friend?

Take pictures of the bullies and let the world know what they are doing

While ignoring the bully is the best way to go, he has to be ready for anything. I've had a lengthy experience with bullies in elementary, middle and high school, and what they want is to provoke a reaction from the victim. Any reaction. While some will stop bullying after being ignored, others will keep going and will go to lengths to get his attention.

The most important thing here is to not let their insults affect him in any way, even personal ones. Apart from ignoring them, let them know their insults won't hurt or budge him. And it's important to be ready for anything. Bullies are troubled people, and I've seen why firsthand.

My friends and I were part of the geek clique in school and had bullies. We all dealt with them in our own way. I grabbed my bully by the neck and choked him against a wall until he almost passed out in gym class in front of everybody. And not just regular choking. I mean feet off the ground and watching his eyes roll into his head choking. I asked him if he was going to keep bullying me and I held him in the air until he said no. I was never bullied again.

My friend took karate classes and beat 3 bullies in the parking lot. They tried to jump him when the rest of us were not around. He left all 3 of them laying on the ground. I mean they were swollen and bruised and bloodied. He was never bullied again. Once the bullies realized our clique wasn't a easy mark, they left everyone else alone.

Violence isn't always the answer, but it is a answer. Bullies like to look for the weakest targets. So you can either stick with someone who is strong, or become strong. Either that or become popular. The weird way that high schools work is that jocks will respect popularity too.

Bullying is such an easy fix these days I'm surprised that you haven't found a solution yet.

This is actually quite simple to resolve and there are different options.
The 1st option of ignoring them and not stooping to their level is probably the worst thing to do at this point. For starters, ignoring them and not fighting back hasn't caused these bullies to leave him alone, so why would that work now? Waiting until this passes and going to college is also not the solution. What if he commits suicide between this time and now? Action needs to be taken this very moment. Not in a week or a month, but now.

Right now, you friend is seen as prey and they are the hunters. When an animal spots his prey, they want to minimize injury to themselves at all costs. If there is resistance, then the hunter will go elsewhere and leave that prey alone. But I understand that your friend cannot stand up for himself, especially against a crowd of these people. This is where you or any of his other friends NEED to step in and stand up against these bullies collectively. If you can single one of these guys out as a group, then you will win the battle for that time and they will slowly stop bullying your friend.

Status also plays a huge role in this as well. Clearly your friend is seen as a the kid who gets picked on at his school. Having someone popular stand up to these bullies will also prevent these bullies from bothering your friend. The higher the status of you or your friends the better. By simply standing up for your friend will prevent your friend from committing suicide. 

I hope this helps.

In my experience with bullying, I don't think anyone recognizes what they're doing as bullying or even as mean-spirited. They usually seem to just think they're being funny. If you kind of pretend you get it and act like you're in on the joke they will be friendlier.

The common answer of ignoring never did much good as far as I could tell. People can tell when you're deliberately ignoring them and they take that as an indication that they're getting to you, which isn't going to discourage them.