welcome pturner,
as far as i know, your husband's brother is not correct in saying that the will would override the quit claim deed. you should note that a will comes into effect after the death of the grantor whereas the quit claim deed will come into effect immediately during the lifetime of the grantor. if your father-in-law had quitclaimed the property to you 3 years back, then it's your property now. the will cannot override the property deed.
as far as i know, your husband's brother is not correct in saying that the will would override the quit claim deed. you should note that a will comes into effect after the death of the grantor whereas the quit claim deed will come into effect immediately during the lifetime of the grantor. if your father-in-law had quitclaimed the property to you 3 years back, then it's your property now. the will cannot override the property deed.