Is the 'Asr prayer valid for someone who combined Dhuhr and 'Asr prayers during the 'Asr time due to سلس ( سلس البول: urinary incontinence, سلس الريح: flatulence incontinence, سلس الغائط: fecal incontinence), and he caught most of it before sunset, while the last rak'ah was after sunset, taking into consideration that the ablution of a person with سلس becomes invalid when the time for that prayer ends?

It is permissible to combine two prayers (Dhuhr and Asr, Maghrib and Isha), either by advancing or delaying them, for someone suffering from urinary incontinence, provided that they do not intentionally delay the prayer until a time too short for both prayers or until the time of necessity. Regarding the nullification of ablution by the expiry of the Asr prayer time during the prayer, it is nullified according to some jurists, unless it is the Friday prayer, and in that case, the prayer must be made up.