Hasan al-Basri (may Allah have mercy on him) said: The Sunnah regarding the grandfather has been established that Sayyiduna Abu Bakr (may Allah be pleased with him) gave the grandfather the status of the father, but (today) people have adopted a different opinion.
Hadith Referenceسنن دارمي / من كتاب الفرائض / 2946
Hadith Takhrijاس اثر کی سند اشعث بن سوار کی وجہ سے ضعیف ہے۔ دیکھئے: [ابن منصور 54] ، اس میں ہے کہ اگر زمامِ حکومت میرے ہاتھ میں ہوتی تو میں دادا کو باپ کا درجہ دیتا۔ اور اس کی سند صحیح ہے۔
Brief Explanation
(Commentary on Ahadith 2937 to 2946) From all these traditions and the testimonies of the Companions and Followers (rahimahumullah), this issue is established that when the father of the deceased is not alive, the father's share will revert to the grandfather, meaning that in place of the father, the grandfather will be the heir. Further details are coming ahead.