His father and paternal uncle died, then his grandmother died. Does he inherit from her?

Praise be to Allah.

Firstly: 

Your father's estate is to be divided between his two male sons, his wife and his mother, and the paternal uncle does not get anything from your father's estate, and neither do his (the uncle’s) sons or the paternal aunts, because they are prevented from doing so by the presence of the male sons. 

The mother gets one sixth, the wife gets one eighth and the rest goes to the two male sons. 

Your paternal uncle’s estate is to be divided among his children, both male and female, and his wife and his mother, and you and your paternal aunts do not get anything from the estate of your paternal uncle. 

So the mother gets one sixth, the wife gets one eighth and the rest goes to the children, with each male getting the share of two females. 

Thus it is clear that your grandmother has a share in the estate of your father, and a share in the estate of your paternal uncle, namely one sixth from each. So her share of the house is two sixths, i.e., one third. If your father or paternal uncle had other wealth, apart from the house, then she takes her share of that too. 

Secondly: 

If the grandmother has died, then her estate goes to her heirs who are: her three daughters, who get two thirds, and the rest goes to the daughters of her two sons and their brothers, with each male getting the share of two females. 

Based on that, then one third of the grandmother's estate is to be shared between the four males and the two daughters. 

And Allah knows best.