The ruling on leaving off prayer for an excuse and how it is made up

His final question says: What is the ruling on one who leaves off five prayers for an excuse, such as the lack of ritual purity, for example? And how does he make up these prayers? And how are they made up if they are more than five prayers? And likewise, how are they made up if they are fewer? Please inform us, may Allah reward you with the best reward.
Answer: Many of the sick may be ignorant of the legal ruling regarding prayer, so they become lax and delay the prayers, hoping, in their opinion, that they will be healed so that they can make them up in a better state. This is a mistake. It is not permissible for the sick person to delay the prayers; rather, he must pray them according to his condition. The Messenger of Allah (peace and blessings be upon him) said to 'Imran when he was afflicted with the disease of hemorrhoids: So he (peace and blessings be upon him) ordered him to pray according to his condition and did not allow him to delay them. Also, because prayer is obligatory in its time, it is not permissible to delay it beyond its time. However, it is permissible for him to combine the midday and afternoon prayers, and the sunset and night prayers, due to illness, just as the traveler combines them. As for delaying them entirely beyond their time, delaying two sets beyond their time, and delaying the dawn prayer beyond its time, this is not permissible. Rather, it is obligatory for him to pray within the time, even if on his side, or even if lying on his back. For Allah says: [Surat al-Taghabun: 16]. And the Prophet (peace be upon him) says: One should be alert to this and remind people of this matter. It is incumbent upon every believer, male and female, to be alert to this matter and remind people of it, and that it is not permissible for the sick person to delay, but rather it is obligatory for him to pray the prayer in its time, whether he is standing, or sitting, or on his side, or lying on his back, according to his ability: [Surat al-Taghabun: 16].
And if he is unable to pray with water, he prays with dry ablution. For example, if it is difficult for him to use water because of the illness, he uses dry ablution, meaning: he performs dry ablution with dust, he rubs himself with dust, he strikes the dust with his hands and wipes his face and his palms with them, and it takes the place of water when one is unable to use water, or when one is unable to use it due to illness, and praise be to Allah. And likewise, if his clothes, or his bed, contain ritual impurity, and it is not easy for him to wash the clothes or replace them, and it is not easy for him to wash the bed or replace it, he prays according to his condition [Surat al-Taghabun: 16], and his prayer is valid. But if he delayed out of ignorance, he must make them up in order, even if in one moment. He makes them up in order: he prays the dawn, midday, afternoon, sunset, and night prayers in sequence. Even if he prays them at one time, immediately, that is good. The point is that it is obligatory for him to hasten and rush to make up the missed prayers, and not to delay or postpone them after he becomes able to do so.