What steps can I take to help my father?

My father is 'only' 67. He's always had mental problems, but managed to keep stead jobs and a family. In past, though, he had 'mental breakdowns' and was hospitalized on a couple occasions. After my mother died in 2007, he has gone down hill. He is 5'10" and weighs 118lbs. He doesn't eat. He doesn't take his medication unless aggressively directed to, and needs to have someone manage them for him. He is a mess with money and throws it away on splurges and things he never uses. He sleeps in a chair, and hardly ever bathes unless directed to. He's said suicidal things, and now he seems delusional and paranoid. He talks about people trying to get him, about hearing things, etc. He sees a doctor, but just a general MD who has him on Risperdal and Lexapro.

My question is basically this: I am a 23 year old who lives with my father, and it is my father who makes all the income. I can't work due to a physical disability, basically, and we live off his pensions. I have no legal work in my favor, like a power of attorney or guardianship. I just have no idea what to do. I fear he is going to hurt someone or more likely himself. I have an older sister who can help, but she lives away from home and couldn't take him to live with her.

What would be some first steps? I thought about talking to his doctors, but maybe they won't speak with me about his mental state due to privacy stuff. I think he needs to at least be in a mental hospital short term to have people aggressively monitor his medication, diet, sleep, and general health. I don't think he will go though, and he can sometimes seem very reasonable and so I think he would argue against it.

The only thing I have been told so far is that I may need to see an Elder Law Attorney, but I have absolutely no income. What on earth can I do? I'm stuck here with a father who is basically dying because he can't help himself, and I feel powerless to do anything!