After our mother died, my father remarried. He added his new wife as an owner of the family home, and they now own our house as "tenants by the entirety." My father has told my sister and me that upon his death the home will go to both of us. He showed us his will, which appears consistent with his desires. Are we protected? Is the will sufficient? Is there anything more we should be doing?
First, I want to make an important correction to your question. You state that your father and his new wife own "our" house. Unfortunately, although it may once have been the family home, it is not your house now. I assume that it was your father's and mother's house, and after your mother died your father became sole owner. He added his new wife to the title, and that is his clear choice -- and his right.
For all practical purposes, your father's will is meaningless as it relates to the house, and it will not accomplish what you believe to be his intentions. In general, a person's will applies only to assets in the decedent's individual name. In your case, the house is no longer in your father's individual name.
The legal concept of "tenants by the entirety" is reserved exclusively for a husband and wife. This means that your father and stepmother both own the entire property as one entity. It is not divisible, and neither spouse can sell or in any way dispose of an interest in the property without the consent of the other.
When one spouse dies, the other spouse automatically becomes the full owner of the entire property. This is what we lawyers call an act "by operation of law." No probate is required under such circumstances. It appears that your mother and father also owned the house as "tenants by the entirety," and when your mother died, the house automatically went into your father's name alone.
There is nothing your father can do in his will to defeat that legal occurrence. Even if your stepmother has a will leaving the property to you and your sister upon her death, she can change the terms of her will after your father's death.
Needless to say, this is not a pleasant subject. It is often difficult to talk to parents about death and inheritance. But the fact remains that your father's stated intentions will not be carried out as he has structured his legal affairs. I can foresee a major confrontation, and possibly litigation, after your father dies.
You should discuss the situation with your father. Keep in mind, however, that he has the absolute right to dispose of the family home as he wants; it became his house upon your mother's death, not yours.
If he really wants to leave the property to you and your sister, he will have to change the title to the property. And even then, depending on where the property is, his wife may retain statutory rights to a portion of his estate -- which may include the house.
Here are some suggestions for your father to consider: