What must a father do for his repentance to be accepted after he used to follow sorcerers and charlatans, and is his current illness (angioedema) related to that?

The repentance of a servant for all sins is accepted if it fulfills the conditions of sincerity to Allah, remorse for what was done, abandonment of the sin, and a firm resolve not to return to it. One must hasten to repent before the death rattle. We ask Allah to cure your father and make his illness an expiation for his sins.