All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad is His slave and Messenger. We ask Allaah to exalt his mention as well as that of his family and all his companions.
If there is no one else to take care of your father while recovering from his disease and during medical treatment, then we hope that there is no harm on you in delaying and not performing Hajj (pilgrimage) this year, as there is a great harm in leaving your father in this state. However, if there is someone to take care of him during his sickness, like your sister or relatives, or trustworthy servants, then you have to take the initiative to perform the obligation of Hajj, as it should be performed as soon as one is able according to the correct opinion of the scholars.
Allaah knows best.