Is it permissible to supplicate for the healing of a person afflicted with a terminal illness (AIDS), even if the hope of recovery is very low (20%), and would this be considered a contravention of Allah's divine decree and destiny?

The suitor, before the marriage contract, is considered a stranger (non-mahram), and it is impermissible to establish a relationship between a young man and a non-mahram young woman. It is permissible to supplicate for the suitor's recovery, for supplication is part of divine decree that repels divine decree, and it is beneficial in all circumstances. There is no Muslim who supplicates but that Allah grants him one of three things: either his supplication is hastened for him, or it is stored for him in the Hereafter, or an equivalent amount of evil is averted from him. If he does not recover or if the marriage to him does not materialize, then you must remove your attachment to him and trust that all good lies in what Allah decrees, in accordance with the Almighty's saying: "But perhaps you hate a thing and it is good for you; and perhaps you love a thing and it is bad for you. And Allah knows, while you know not."