Is it necessary for someone who prays sitting on a chair, out of fear of passing wind, to perform ablution (wudu') while sitting? And how should they act if they do not find a seat for ablution? And is praying sitting obligatory for them if there is a possibility of passing wind during bowing (ruku') or prostration (sujud)?

If someone fears that wind might be expelled if they pray standing, then they should pray sitting if sitting prevents the wind from being expelled. Otherwise, there is no benefit in sitting. Some jurists are of the opinion that such a person should pray standing, because preserving the pillar of standing is more important than preserving the condition of ritual purity. This issue is one of ijtihad (definition), and there is latitude in the matter. There is no evidence among scholars indicating that one must perform ablution sitting if they fear the expulsion of wind during ablution.

One must beware of intrusive thoughts (waswās) and turn away from them.