Jesus says that we should go out and pray for the sick and then God will heal them.
Anyone who believes and follows Jesus can go out and pray for the sick and cast out evil spirits in Jesus’ name.
The name of Jesus is above all other names, therefore all diseases must let go when in faith you speak out and command in the name of Jesus.

Gospel of Mark 16:17-20
Signs shall follow those who believe this.  In my name they shall cast out evil spirits.  They shall speak with new tongues.  They shall take serpents in their hands, and if they drink any deadly poison it shall not harm them.  They shall lay hands on the sick, and they shall recover.”  After the Lord Jesus had spoken to them, he was taken up into heaven and sat down at the right hand of God.  And they went out and preached everywhere, and the Lord worked with them and confirmed the word by the signs that accompanied it.