How do you help someone who is severly depressed and probably needs medication when they refuse all help?

If he isn't willing to get the help there really isn't much you can do. It's a crappy situation to be in I know. Try talking to him and explain how much it is affecting you seeing him in this current state. Try to reason with him and encourage him to at least see a doctor once and go one from there. Don't make him promise anything just take it a day at a time, and explain it to him like that. Sorry you have to deal with this, stay strong and good luck!