As for the rulings of tayammum (dry ablution):

The author cites, to prove that tayammum is permissible for someone who is wounded or ill, the ḥadith of Jābir (may Allah be pleased with him):

“We set out on a journey and one of our men was struck by a stone that split his head. Later he experienced a nocturnal emission and asked his companions (about what to do)… The Messenger of Allah ﷺ said: ‘They killed him—may Allah kill them! Why did they not ask when they did not know? The remedy for ignorance is to ask. It would have sufficed him to perform tayammum, then squeeze out or bind a cloth over his wound, wipe over it, and wash the rest of his body.’”

This narration was recorded by Abū Dāwūd, Ibn Mājah, and al-Dāraqutnī, and Ibn al-Sakan deemed it sound.

I say: Al-Bayhaqī, Ibn Ḥajar al-ʿAsqalānī, and others graded this ḥadith weak. Yet it has a corroborating chain from Ibn ʿAbbās that raises it to the level of ḥasan. However, the wording “to squeeze…,” and what follows, is absent from that supporting report; it is a weak, objectionable addition unique to this feeble chain.

See al-Talkhīṣ for further discussion.