Praise be to Allah.
Zakaah is prescribed for several purposes, one of which is meeting the needs of the needy. Undoubtedly the sick person who is not able to earn an income and does not have money that he can spend on medical treatment is one of those who are entitled to zakaah, because he is included in the general meaning of the verse in which Allah, may He be exalted, says (interpretation of the meaning): “As-Sadaqat (here it means Zakat) are only for the Fuqara (poor), and Al-Masakin (the poor)…” [at-Tawbah 9:60].
In fact such a one is more entitled to it than other poor people, because he is poor and unable to earn a living. But the basic principle is that zakaah should be given directly to the poor and needy person, then he may dispose of it however he wishes, according to whatever need he wants to meet.
The basic principle is that zakaah should be given directly to the poor person, then he himself should use it to pay off hospital and medical bills.
It may be permissible for the charity to do that instead in two cases:
If the charity is paying off medical costs that are proven to be a debt owed by the sick person, such as paying for hospital accommodation, doctors’ services, and so on. In this case the sick person is also a debtor, and it is permissible for the giver of zakaah to give it directly to the creditor.
The second case is if that is easier for the sick person and is better in his view, such as if he does not have anyone who can serve him or buy medicine for him, or he fears that if he receives the cash directly, he will not dispose of it properly. In this case it is permissible to buy medicine for him.
Please see the answer to question no. 138684, in which we quoted a fatwa of Shaykh Ibn Baaz which says that it is permissible to buy specific items for a poor person from zakaah funds when there is a need to do that.
Based on that, there is no reason why zakaah cannot be given to sick people for the purpose of doing surgery or buying medicine, or anything else that will meet their needs, but that should be done after confirming that they are entitled to zakaah.
The Standing Committee for Issuing Fatwas was asked:
… Does the charity have the right to make use of zakaah funds and use them to pay for medical treatment, care and rehabilitation of children with disabilities, the poor and others who need care?
There is no reason why zakaah funds should not be used for poor people with disabilities.
End quote from Fataawa al-Lajnah ad-Daa’imah li’l-Ifta’ (9/464)
and Allah knows best.