Allahu tawala keeps good relation who maintain good relation with the relatives

The deed to be rich and live longer

وَعَنْ أَنَسٍ رَضِيَ اللهُ عَنْهُ أَنَّ رَسُوْلُ اللهِ صَلَّى اللهُ عَلَيْهِ وَسَلَّمَ قَالَ‏:‏ ‏‏ مَنْ أَحَبَّ أَنْ يُّبْسَطَ لَهٗ فِيْ رِزْقِهٖ، وَيُنْسَأَ لَهٗ فِيْ أَثَرِهٖ، فَلْيَصِلْ رَحِمَهٗ -‏
متفق عليه‏
Meaning:
Hazrat Anas (May Allah be pleased with him) reported: Messenger of Allah صَلَّى اللهُ عَلَيْهِ وَسَلَّمَ said, "He who desires ample provisions and his life be prolonged, should maintain good ties with his blood relations".
Bukhari and Muslim
Reference : Riyad as-Salihin 319

How one can behave well with his father after the death of his father

عَنْ عبدالله بن عمر قَالَ قَالَ رَسُولُ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ من أحبَّ أن يصِلَ أباه في قبرِه فليصِلْ إخوانَ أبيه بعدَه
المصدر: الترغيب والترهيب
خخلاصة حكمه: [إسناده صحيح أو حسن أو ما قاربهما]
Meaning:
It is narrated on the authority of Abdullah ibn Omar that the Messenger of Allah صلى الله عليه وسلم said: “Whoever wants to maintain ties with his father in his grave, let him maintain ties with his father’s brothers after him.”

Its chain of transmission is authentic, good, or close to that.