father dies leaving stepmother right of survivorship

What is the name of your state (only U.S. law)? Texas
My dad dies a year and a half ago. no one hsa mentioned will. my brother has located a right of survivorship if one dies the other gets it. the problem is there are half brother and sisters and my stepmother is the survivor. it appears that my half brother says that when my stepmother dies he will have the right to split the estate. I can see that we will get nothing because lack of communication. Don't we have right since we were his first children? how could we ever be protected and receive anything. they are in total contol now. and they are not talking. it seems wrong and we will get left out. in the survivorship there are no witnesses just a notary and it could have been drawn up when dad was sick back in 1990.

What do you mean (or what does this borther mean) by "..located a right of survivorship.."? A right of survivorship is a form of title for specific assets. Are you referring to a specific asset? The house?

No, you don't have any particular rights as "first" children. Your father was free to provide for disposition of his assets as he saw fit.

When your srtepmother acquires ownership of any assets, she is also free to dispose of them as she sees fit.

If you are going to fight for anything, now is the time to do it. Consult with a few attorneys and retain one.