As long as the felon is no longer in prison, he is free to visit anybody he wants, anywhere (unless there is an order of protection against him).
Most likely the prison will not approve an ex felon. Felons are suppose to steer clear of other felons. You must be approved by the prison to be be put on the inmates visiting list.
I'm a convicted felon and I have a friend that is in a federal prison and he wants me to visit him, would I get a approved to see him if I fill out the paper work