I'm not licensed in NC, so I can only answer in general terms. There are two questions you need to answer. First, did your husband survive his father under the terms of the father's will and the applicable law? Typically wills have a requirement that a beneficiary survive by 30 or 60 days. If he survived, then your husband's estate is entitled to all future distributions from the father's estate. If not, distributions go to the contingent beneficiary under the father's will. That could be anyone, but typically would be any children of your husband and, if none, it would go to his siblings who survived.
The second question is did your husband have a will? If he survived, then his will governs the distribution from his estate. If not, his estate is distributed in accordance with the intestacy statute of NC.
I'm sorry about your recent losses. Your question is great and it's one I get asked quite frequently. What if anything you are entitled to under your father-in-law's will, depends on what his will says and whether or not your husband died after him or before him. If your husband died after your father and the will left a bequest outright to him and he survived your father-in-law by any specific time designated in the will, then the bequest will pay out to your husband's estate. If your husband left everything by his estate plan to you, then you will receive the bequest which paid out to his estate from his father's estate. However, some wills mandate that the beneficiary survive the deceased by 6 months or more. If your husband didn't survive his father by such period of time then you won't inherit. If your husband passed before his father then you probably won't inherit unless your father-in-law's will states that such property passes to you if his son predeceased him. If not, then you won't receive anything. The estate will pass by your father-in-law's will.