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
وَحَدَّثَنَا مُحَمَّدُ بْنُ رَافِعٍ، حَدَّثَنَا عَبْدُ الرَّزَّاقِ، عَنِ ابْنِ جُرَيْجٍ، أَخْبَرَنِي نَافِعٌ، عَنِ ابْنِ عُمَرَ، أَنَّ عُمَرَ، اسْتَفْتَى النَّبِيَّ صلى الله عليه وسلم فَقَالَ هَلْ يَنَامُ أَحَدُنَا وَهُوَ جُنُبٌ قَالَ " نَعَمْ لِيَتَوَضَّأْ ثُمَّ لْيَنَمْ حَتَّى يَغْتَسِلَ إِذَا شَاءَ " .
Ibn 'Umar said: 'Umar asked the verdict of the Shari'ah from the Apostle (ﷺ) thus: Is it permissible for any one of us to sleep in a state of impurity? He (the Prophet (ﷺ) said: Yes, he must perform ablution and then sleep and take a bath when he desires.