Even sickness for a Muslim is a blessing of Allah. The reason for this is that if a pious person falls ill, then his status is elevated and if a sinner falls ill then his sins are forgiven.
To visit a sick person is known as “Iyaadat.” This is to show human kindness and it is a means of earning Sawaab. Most of all it is the Sunnah of the Prophet (sallal laahu alaihi wasallam).
When a person visits a fellow Muslim who is ill, then he gains the Mercy of Almighty Allah and the gift of Jannat. The Prophet (sallal laahu alaihi wasallam) has stated: “If a Muslim visits his fellow Muslim brother who is ill in the morning, then 70 000 Angels pray for that person until the night and if he visits at night then they pray for him till the morning, and due to his Iyaadat, he gains a garden in Paradise.” In another Hadith, it has been narrated that if a person makes fresh Wudhu and intends to visit an ill person only for Sawaab, then he is kept away from Hell as far as the distance of a 70 year journey.
It is also Sunnah to allow the sick person to eat whatever he desires. When visiting a sick person, one should not be rowdy, unpleasant or unkind. Do not visit the sick person for a long period. You should make D’ua and then take leave. When visiting the sick also ask the sick person to make Du’a for you since their Du’as are readily accepted.