Is it permissible for someone suffering from urinary incontinence to combine two prayers with one ablution if the time difference between them is short, and is he required to repeat the prayers he performed in this manner?

The owner of chronic discharge ( سلس ) must perform ablution for each prayer, according to the majority of scholars. Delaying Dhuhr prayer until close to Asr does not change this ruling. Prayers performed with the ablution of the previous prayer must be repeated, unless there is extreme hardship, in which case it is permissible to follow the Maliki school of thought regarding past prayers, and then resume acting according to the view of the majority.