Is my mom's estate./children entitled to house?

my mom recently passed away (no willl). She was deceased by my step-dad (will dated 1993). His will left everything to my mother unless they died together or she predeceased him, in which case his assets would be split between his 2 daughters from a previous marriage. He also named my mother as executor except in the case she was unable, then he named his eldest daughter (also deceased) as executor. My problem is my mother did not do anything with my stepfather’s estate which only included their house which was in my stepdad’s name. I have received two different answers as to how to proceed. One lawyer it should be included in her estate because she survived him. The other lawyer said that because she did not have the house switched to her name it would default to his estranged grandchildren and his surviving daughter. The surviving daughter is in agreement that it should go to my mom's estate.