My boyfriend hurt his shoulder in federal prison and has received no medical attention can he sue the federal government?

He has received little to no medical care for his shoulder since he has hurt it he is still currently serving his sentence in a federal prison and in constant pain everyday. I think he has dislocated his shoulder and has a big knot on his shoulder that has been there since this happened which has been almost a year since it happened. the prison docter told him that it need some outside attention but they still have never done anything. what kind of attorney would he need? does he have any kind of case against them?