It depends. The law stipulates that daughters-in-law and sons-in-law are obliged to help their parents-in-law materially and financially as part of the obligation to provide support (art. 206 C. civ.). The death of your husband does not terminate this obligation (Lyon Jan. 25, 1967).
On the other hand, if you had no children with your husband or if they are deceased, this obligation ceases (art. 206 C. civ..).