My mother died and left house to my sister but my father died years ago making no will is it the case that the rest of us were entitled to one third now is it the case that maybe my mother had no right to leave the house only her 2 thirds what do you think tks

First its not a good idea to piggyback your question on another thread. This can lead to confusion. So I've moved your question to its own thread.

Second ANY question on law needs to include your general locale as laws vary by area.

If mom owned the house jointly with dad, then she may have gotten the house under right of survivorship and it was not included in your father's estate. If she was not a joint owner, then the house should have been distributed according to local laws of inheritance, which, since we don't know where, we can't advise on.