"Umm Habibah said: 'I heard the Messenger of Allah say: It is not permissible for a woman who believes in Allah and the Last Day to mourn for anyone who dies for more than three days, except for a husband; (she mourns for him for) four months and ten (days)." (Using translation from Nasāʾī 3500)
سَمِعْتُ رَسُولَ اللهِ ﷺ يَقُولُ «لَا يَحِلُّ لِامْرَأَةٍ تُؤْمِنُ بِاللهِ وَالْيَوْمِ الْآخِرِ تُحِدُّ عَلَى مَيِّتٍ فَوْقَ ثَلَاثَةِ أَيَّامٍ إِلَّا عَلَى زَوْجٍ أَرْبَعَةَ أَشْهُرٍ وَعَشْرًا»