In Nevada and under common law the estate is now "intestate" that is without a testamentary disposition. You have a right to be notified of any court actions taken regarding your fathers estate.
If a probate has not been opened then I suggest you seek the equivalent of Nevada's "Special Administrator" appointment to take possession of any personal property of the decedent.
You can then Petition the Probate Court for a formal probate.
The previous response points out the critical fact you need to focus on -- intestacy. As a Texas attorney, any specifics that I provide to you regarding division of an intestate estate might be very different from the rules that will govern in the state that your father resided in at the time of his death. If you've been given conflicting information, it's likely due to the variance between how different states deal with this issue when a person dies without a Will.
Simply for example, Texas is a community property state. Our laws regarding what is referred to as "intestate succession" take into account the marital status of the decedent and what share of his or her estate is considered marital (community) property and what part is considered separate property. The result of your situation in Texas is a division of the decedent's estate among the second wife and the children of the first marriage.
Take a moment to make a few calls and visit with an attorney in the state where your father resided at death. Pose your question to them in order to understand how intestacy is treated there, particularly with children from a first marriage. Odds are you'll find that the result is not one-sided in favor of the children or the spouse, but rather subject to some sort of division among them. In any event, after determining what, if any, interest you might have in your father's estate, consider your options to initiate an administration of his estate.
This answer does not constitute legal advice. I am admitted to practice law in the State of Texas only, and make no attempt to opine on matters of law that are not relevant to Texas. This answer is based on general principles of law that may or may not relate to your specific situation, and is for promotional purposes only. You should not rely on this answer alone and nothing in these communications creates an attorney-client relationship.