Answered by Shaykh Faraz Rabbani
Sleeping after Praying Asr: Is it disliked?
It is in itself permitted to sleep after Asr.
Imam al-Tahawi, the great early Hanafi mujtahid and hadith expert, shows in his Mushkil al-Athaar [1.99] that the sounder opinion is that it is permitted (and not disliked) to sleep after Asr, as it is soundly established in hadiths that Ali (Allah be pleased with him) did so, and the Prophet (Allah bless him and give him peace) did not object. As for the narrations mentioning otherwise, they are not as soundly established.
However, given the difference of opinion regarding it, it could be superior to try to sleep before Asr if one is reasonably able: the Hanbalis (Allah have mercy on them) and others have stated that it is disliked to sleep during Asr time. [Buhuti, Kashshaf al-Qina`, 1.79]
But if one’s schedule does not allow this, and one seeks to sleep a little at this time in order to be able to get up at night for the night vigil (tahajjud) prayer, it is not disliked.
And Allah alone gives success.