My uncle passed away.

Answer

When your uncle-in-law passed away, the following were alive:

One sister, one brother, one stepsister (same father) and one stepbrother. Besides these, we have understood that he had no wife and parents living. In this case, the only heirs are the one full brother and one full sister. The brother inherits two thirds and the sister one third. The stepbrother and stepsister do not inherit in this case.