Is the 'Asr prayer valid for someone who prayed three rak'ahs of it before sunset and one rak'ah after it, knowing that the ablution of a person with urinary incontinence is invalidated when the time for prayer expires?

A person afflicted with سلس (incontinence) is not permitted to delay two prayers when intending to combine them until their time becomes constricted. If he does so and the time expires, his ablution becomes invalid according to some scholars, except during Jumu'ah prayer, where his ablution does not become invalid if the time expires while he is performing it, because it is not to be made up.