What is the ruling on a wife caressing her husband during the daytime in Ramadan without ejaculation, and does this necessitate ghusl and break the fast, and is she sinful for not obeying him, and are there any health harms in it?

Masturbation is always forbidden. During Ramadan (definition), it invalidates the fast if it leads to the emission of semen. As for mutual masturbation between spouses, it is permissible, but it becomes forbidden during the day in Ramadan if it is highly probable that ejaculation will occur, and it is disliked if it is not highly probable, as it is similar to kissing. Ghusl (definition) (ritual bath) is only obligatory after the emission of semen. Touching the husband's private parts does not obligate ghusl upon the wife, but it does invalidate her ablution (wudu').