My mother died suddenly without having made any will. I think she would have definitely given Sadaqa if she had been able to speak. Would she have a reward if I gave Sadaqa on her behalf? He (the Holy Prophet) said: Yes.  

أَنَّ رَجُلاً أَتَى النَّبِيَّ ﷺ فَقَالَ يَا رَسُولَ اللَّهِ إِنَّ أُمِّيَ افْتُلِتَتْ نَفْسَهَا وَلَمْ تُوصِ وَأَظُنُّهَا لَوْ تَكَلَّمَتْ تَصَدَّقَتْ أَفَلَهَا أَجْرٌ إِنْ تَصَدَّقْتُ عَنْهَا قَالَ نَعَمْ  

" She did not make any will," as it has been reported by Ibn Bishr, but it was not reported by the rest of the narrators.  

عَنْ هِشَامٍ بِهَذَا الإِسْنَادِ وَفِي حَدِيثِ أَبِي أُسَامَةَ وَلَمْ تُوصِ كَمَا قَالَ ابْنُ بِشْرٍ وَلَمْ يَقُلْ ذَلِكَ الْبَاقُونَ