From the lessons on al-Mundhiri’s “Al-Targhib wa al-Tarhib”: “Encouragement to visit the sick and its confirmation, and encouragement to supplicate for the sick”

The Shaykh : The purpose and the goal of visiting the sick sometimes differ and sometimes coincide. The coincidence is that the purpose of visiting the sick, always and forever, is to remember the state of man, that he fluctuates from health to illness, and from illness to death. Therefore, you will hear tonight or later—I do not know—some hadiths in which there is a command to visit the sick and follow the funerals. The reasoning given in them is that they remind one of the Hereafter. So, visiting the sick in general has this benefit, and it has this legal goal, which is remembering the Hereafter. I say this about every visit, because there is a detail regarding the visit: is it always and forever a collective obligation, or does it sometimes become an individual obligation? This varies according to the state of the patient or the nature of his illness, and according to whether he has someone to attend to his needs and affairs, or whether none of that exists at all. In the first case, that is, when the patient has someone to help him and attend to his service in everything he needs, then the visit of others to him is from the category of what is recommended and virtuous. But if there is no one to help him, like some of the poor people who are described in the Arabic language—and there is no blame in that—as the destitute, those who are not heeded, then for such people, it is an individual obligation for some individuals to stay with him, even if it is by taking turns, to attend to his service.
So, visiting the sick is sometimes obligatory and sometimes recommended. It is obligatory when there is no one to help him in his illness, and there is an individual obligation upon certain people who must attend to his service, as we mentioned. But if someone has been found to fulfill this obligation, then anything beyond that is from the category of noble morals and the virtues of recommended matters, and it is not an individual obligation. This is among the wisdoms of the Shari'ah, because you know that the sick person, or at least some of the sick, complain of the many visitors who come and go to him. Therefore, it is inherited from the Salaf that the visit should be the interval of a camel’s milk; that is, a very short time, the amount of time it takes to milk a camel. This is so that the patient does not complain of the visitor staying with him in his place. So, this is the detailed statement on visiting the sick: in general, it is prescribed to remember the Hereafter, and in some cases, it is commanded to help the patient in his illness. And that, of course, may necessitate material assistance if he is poor. In this case, it is an individual obligation upon some people.
This is what can be said in detail about the ruling on visiting the sick.