Inheritance from a property on rent
Q: We were three brothers and two sisters (all married). Our elder brother lives abroad. While 2 brothers and 2 sisters live in Karachi. We have one double story house in inheritance from our father in which myself and my younger brother lived till 2015. When I got company accommodation then we shifted to that house with my younger brother. As mutual understanding, we allowed one sister to live in one portion and another one to get rental income.
Now the issue is that my younger brother passed away recently (30-Jan-21) and he left two boys and one widow behind. His widow is in iddat and has no means of income. So what should be her right and her boys rights regarding their grandfather's house and its rental income.
Please advise in the light of Islamic law of inheritance.