Is it permissible for someone who claims to have a chronic illness that prevents him from maintaining ritual purity (wudu') to abandon prayer (salat)?

A Muslim must perform prayer according to their ability: standing, if unable then sitting, if unable then on their side, if unable then by nodding their head and intending with their heart, as the Prophet (peace be blessings be upon him) said: "Pray standing; if you are unable, then sitting; if you are unable, then on your side."

Similarly with purification: whoever is able to use water should perform ablution (wudu'), and if unable, then perform tayammum (dry ablution). If one can find neither water nor dust, then, according to the preponderant opinion, they should pray without purification.

The person in question must perform ablution for each prayer after its time has begun. Incontinence does not affect him if it is constant for most of the time. He must repent and make up the prayers he missed.