What is the ruling on one for whom Hajj is difficult due to illness?

The Shaykh : And this woman says: My husband has not performed Hajj throughout the past years because his workplace did not allow him to do so. Now he has been retired, but he has been afflicted with an illness that makes Hajj difficult for him. What is his obligation? Please advise us, may Allah reward you with good.
The answer, O mother of 'Abd Allah, is that he owes nothing until he is able to do so, due to the saying of Allah the Exalted: . However, if this illness is not expected to end and he has money, it is obligatory for him to appoint someone to perform Hajj on his behalf. If the illness is expected to end, he should wait until it ends and then perform Hajj.