What is the ruling for someone who cannot control their ablution due to a colon surgery?

For someone with a valid excuse, substances such as blood, pus, urine, feces, or discharge that come out from the place of excuse and soil their clothes do not prevent prayer as long as the excuse continues. This is because it is not possible to avoid them while the excuse persists. (Ibn Abidin, Radd al-Muhtar, 1/306-307)

A person who has undergone colon surgery and continuously passes stool, or who passes stool without interruption for an entire prayer time and then experiences this excuse at least once in every subsequent prayer time, is considered to have a valid excuse. According to the Hanafi school, such individuals perform ablution for each prayer time and perform their prayers accordingly. With this ablution, they may perform as many obligatory or supererogatory prayers as they wish within that time. (Marghinani, al-Hidaya, 1/34)

According to the Maliki school, however, the ablution of someone with a valid excuse is not invalidated by the entry or exit of the prayer time, but only by something other than the excuse that would normally break ablution. (Ibn Rushd, Bidayat al-Mujtahid, 1/41; Desuqi, Hashiya, 1/114-118) If the condition of excuse causes a person significant hardship and serious difficulty in performing ablution, it is permissible to follow this opinion of the Maliki school.

Source: T.C. Diyanet İşleri Başkanlığı, Din İşleri Yüksek Kurulu