He, sallallaahu ‘alayhi wa sallam, visited him when he was sick:

that the Prophet of Allah, sallallaahu ‘alayhi wa sallam, visited Al-’Abbaas when he was so sick that he wished he would die. The Prophet of Allah, sallallaahu ‘alayhi wa sallam, said to him: “O ‘Abbaas, O uncle of the Prophet of Allah, do not wish for death. If you are a good doer, then you can do more good deeds so it will be better for you. And if you are an evildoer, then you are given a chance to seek Allah’s pleasure so it will be better for you. So do not wish for death.”