I don't know what its like to not have a dad because I have one... my son does not... he does have influence of his grandpa, uncles, and great grandpa... but I am is only parent... his dad is in prison in ms.. and I want him to stay there, because I do not think he would make a good dad... but what should I tell my son? What are some questions that may need to be addressed?

How old is your son? I suppose you could tell him Daddy made some really bad choices, so he has to pay for them, I know he will miss out on a lot of really cool things that are going to happen with you. Or you could just go on and on without mentioning it to him unless he starts asking.

I don't know what its like to not have a dad b/c i have one...my son does not....he does have influence of his grandpa, uncles, and great grandpa...but i am is only parent...his dad is in prison in ms..and i want him to stay there, b/c i do not think he would make a good dad...but what should i tell my son? What are some questions that may need to be addressed?
Although you may not feel he is a good dad and he may not be, you are giving your son his opinion. One day he may begin to question everything that is said and find out for himself. One day he may go look for his dad and resent bum-rapping him. I had a dad but not really. My dad beat me severely, kept me in my room from end of school to go to school, and disrespected us in public to instill domination over us from 6 to 12. I never knew a thing about him. What he did, what he knew or who he was was a complete mystery.
The common thread here is that your son and I never knew our fathers. This creates a suffocating void and triggers resentment. Telling a son that his dad was a bum is something I have heard in the dating world repeatedly. Every ex-guy is a jerk and a deadbeat. Every ex-girl is a psycho and money grubbing. Many people are professional victims without an edited history of past events, few have had one sided traumatization by non provocation. We are all imperfect but when we purposely display this to our children as to bias them toward our angry and covert agendas, innocence is slowly robbed from them and if one day they should act out, commit crimes, and lack success, we must blame ourselves. Since, it was us who biased them and molded their way of thinking in the first place.
The thing to do always is the right thing. Maybe if your son wrote his dad in prison, it could change his life and give him something to live for. His dad may wake up from living asleep and begin a story of personal victory. If so you would deserve credit.
I do not feel that I can answer your posting. The first sentence says that you do it all alone, his dad is in prison and is a bad man, and that you have negative feelings. Since you wish for him to stay in prison and don't think he would be a good father, what question can be addressed if you already an answer?
Peace, faith and prosperity