It is permissible for one who is junub to sleep, but it is recommended for him to perform wudu’, and wash his private parts if he wants to eat, drink, sleep, or have intercourse Sahih Muslim 305 b
Arabic hadith text
حَدَّثَنَا أَبُو بَكْرِ بْنُ أَبِي شَيْبَةَ، حَدَّثَنَا ابْنُ عُلَيَّةَ، وَوَكِيعٌ، وَغُنْدَرٌ، عَنْ شُعْبَةَ، عَنِ الْحَكَمِ، عَنْ إِبْرَاهِيمَ، عَنِ الأَسْوَدِ، عَنْ عَائِشَةَ، قَالَتْ كَانَ رَسُولُ اللَّهِ صلى الله عليه وسلمإِذَا كَانَ جُنُبًا فَأَرَادَ أَنْ يَأْكُلَ أَوْ يَنَامَ تَوَضَّأَ وُضُوءَهُ لِلصَّلاَةِ .
Translation
'A'isha reported
Whenever the Messenger of Allah (ﷺ) had sexual intercourse and intended to eat or sleep, he performed the ablution of prayer.