Ok, so I have a charrie in my story of about 3000 words who's in prison, he is a father and he cares about the family. And I want to know how to write him because to me it's very hard, not like you might know so much about this because hopefully none of you were in prison.
It's your story. You need to come up with your character's mood, and there's no one correct answer. Of course, you should do research about what prison life is really like, otherwise you'll be writing a stereotype. First, you'll need to determine what kind of prison it is. Is it a federal penitentiary, or a medium security state prison? Is it divided into separate areas to keep the most dangerous felons segregated from the lesser criminals? What was your character's offense? I'm not asking these questions to get your answers, but rather to encourage YOU to seek those answers and questions.
Well your right I should do some research, but for now the charrie's kind of out of the story but I have plans of him returning.
The mood that you write your character in will (a) reflect his personality, (b) determine how the readers view him, and (c) possibly change his (fictional) life. I can list options if you want, but the final decision is yours. How far are you with the plot? What's that like? Does a later occurrence depend on his going insane, escaping from jail, whatever? How does he view his family? Why is he in prison and was he falsely accused? These are all things to take into account in your decision.
I think that before you write a story about the prison system you have to familiarise yourself with it. Asking us what his mood would be is difficult because he lives in your imagination. What do you think his mood would be? Any of us could give you a generic answer like sad, lonely, angry, etc, but it's not going to be a reflection of your character. As the posts above say, figure out his voice, his motivations and his reasons for being there. When you understand your character then you don't need to ask these questions. Hope this helps
Once you know who your character is, you'll find it easy to see how they'd react in any circumstance. How will he behave around the other inmates, how does he cope with isolation from his loved ones? Try to go beyond the usual prison clichés (exercise yard, shower rape, evil warden) and research what life is really like, also what type of prison he'd be in given the severity of his crime and what restrictions he'd be under. Once you have the character and the environment firmly fixed in your mind, his reactions should come quite easily.