What is the ruling regarding someone who is constantly afflicted with flatulence only during ablution and prayer, which then ceases afterwards, knowing that he cannot maintain his ablution?

The emission of wind nullifies ablution. If it stops for a duration sufficient for ablution and prayer, then it is not considered سلس (incontinence). In this case, one should wait for the period of cessation, then perform ablution and pray, even if praying alone. If waiting for it to stop would lead to the prayer time expiring, then one should perform ablution and pray in their current state. Some scholars have permitted advancing or delaying prayers to combine joint prayers (such as Dhuhr with Asr, and Maghrib with Isha) if the time of the cessation of the impurity is consistent.