Yahya related to me from Malik that Ziyad ibn Sad heard Ibn Shihab say, "The Messenger of Allah ﷺ let his hair hang down his forehead as Allah willed, and afterwards he parted it." Malik said, "There is no harm in a man's looking at the hair of his son's wife or the hair of his wife's mother."
يَقُولُ سَدَلَ رَسُولُ اللَّهِ ﷺ نَاصِيَتَهُ مَا شَاءَ اللَّهُ ثُمَّ فَرَقَ بَعْدَ ذَلِكَ قَالَ مَالِكٌ لَيْسَ عَلَى الرَّجُلِ يَنْظُرُ إِلَى شَعَرِ امْرَأَةِ ابْنِهِ أَوْ شَعَرِ أُمِّ امْرَأَتِهِ بَأْسٌ