My question is in regard to inheritance, the details of the question are below.

You will not like my answer. I am sorry to say that you can't protect yourself now. Only your father can protect you. If, after the death of his first spouse, your father did put everything into Joint Tenancy with Right of Survivorship with his current spouse, the survivor (the current spouse) automatically inherits all property titled that way. This is true even if your father had a prenuptial agreement. Always remember, the title on any property trumps (overrules) any other document. There is no really gentle way to say this, but what all that means is that you are effectively disinherited.  However, consider also that it could have been unintentional: Your dad may have simply been trying to protect his new, young family and avoid the expense of a lawyer to set up a Will or Trust. He may not have understood the rules of Joint Tenancy and so may not have intended to leave you out. You might consider showing him this and asking him to do some formal estate planning which should include a Will and a Living Trust. He could still leave you something, but that, at the minimum, requires him to retitle the property consistent with the planning documents he uses. This is important: Signing a Will or Trust does not change the outcome without retitling the property. Because of the second family, I would suggest he use a good South Carolina Estate Planning lawyer to make sure that all details are completed properly, tax issues are thoroughly understood and planned, and to avoid problems later. To your success,Gale Allison, Principal AttorneyThe Allison Firm, PLLChttp://www.theallisonfirm.comhttp://www.linkedin.com/in/GaleAllison