What should a person do who has not cleansed himself from urine for a period, and his clothes and places of sitting have become impure, making it difficult to purify them, which has led him to abandon prayer?

You must maintain prayer; indeed, abandoning it is one of the greatest abominations. And repent from not performing istinja' (cleaning oneself after relieving oneself), because it necessitates the torment of the grave and is among the major sins. Purify what you are certain has become ritually impure among your clothes by pouring water over it until it overcomes the impurity. As for what you do not know to be impure, rule it pure. It is permissible for you to act upon the easiest opinions to دفع hardship.