It is narrated from Sayyidah Aishah (may Allah be pleased with her) that (sometimes) he (peace and blessings be upon him) would sleep while in a state of janabah and would not touch water.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الطهارة / 974
Sayyidah Aishah (may Allah be pleased with her) said that he (peace and blessings be upon him) would sleep in the first part of the night and stay awake in the last part of the night. Then, if he (peace and blessings be upon him) had a need with his wife, he would fulfil it, and then sleep before touching water. When the first call (adhan) was made, he (peace and blessings be upon him) would spring up at once. By Allah, Aishah (may Allah be pleased with her) did not say that he (peace and blessings be upon him) stood up and took water, and by Allah, Aishah (may Allah be pleased with her) did not say that he (peace and blessings be upon him) performed the ritual bath, but I know what Aishah (may Allah be pleased with her) meant. If he (peace and blessings be upon him) had no need, he would perform an ablution like the ablution for prayer, then offer two rak'ahs.
The huffaz (hadith masters) criticised the wording "before touching water" and considered it to have been taken from someone other than al-Aswad; Abu Ishaq would sometimes commit tadlis (concealing a link in the chain), so they regarded it as one of his tadlis, and they cited as evidence the narration of Ibrahim al-Nakha'i and Abd al-Rahman bin al-Aswad from al-Aswad, which differs from the narration of Abu Ishaq.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الطهارة / 975
Sayyidah Aishah (may Allah be pleased with her) said that when the Messenger of Allah (peace and blessings be upon him) was in a state of janabah and he (peace and blessings be upon him) intended to sleep or eat, he would perform ablution.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الطهارة / 976
The father of Abd al-Rahman bin al-Aswad said: I asked Sayyidah Aishah (may Allah be pleased with her): How was the ablution of the Prophet (peace and blessings be upon him) when he intended to sleep while in a state of janabah? She said: "He (peace and blessings be upon him) would perform an ablution like the ablution for prayer, then sleep."
Sayyidah Aishah (may Allah be pleased with her) said that he (peace and blessings be upon him) would sleep while in a state of janabah and would not touch water.
It is narrated from Ibn Umar (may Allah be pleased with them both) that Sayyiduna Umar (may Allah be pleased with him) said: O Messenger of Allah, can one of us sleep while in a state of janabah? He (peace and blessings be upon him) said: "Yes, he may sleep after performing ablution."
The Shaykh said: Abu al-Walid narrated to me: I asked Abu al-Abbas bin Shurayh about these two hadiths, and he said: Both narrations have one ruling. In the hadith of Aishah (may Allah be pleased with her), what she meant was that the Prophet (peace and blessings be upon him) would not touch water for the ritual bath. The hadith of Umar (may Allah be pleased with him) is explicit (mufassar), mentioning ablution, and we act upon it.
The hadith of Abu Ishaq al-Sabi'i is sahih (authentic) in terms of narration, because Abu Ishaq made clear that he heard it from al-Aswad in the narration of Zuhayr bin Mu'awiyah from him; and when a mudallis who is thiqah (trustworthy) makes clear that he heard it from the one he narrates from, there is no reason to reject it.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الطهارة / 977