Is it permissible for a girl who has left behind a mother, a father, and two brothers—these two brothers having no share in the inheritance—to make a bequest to them? And would she be considered in violation of the hadith: "There is no bequest to an heir"?

What is forbidden by Sharia is to bequeath to an heir. However, it is permissible to bequeath to a non-heir from among the relatives, provided that it is within the limits of one-third of the estate or less. Indeed, it is recommended to bequeath to non-inheriting relatives, and some scholars have gone so far as to deem it obligatory. Therefore, the aforementioned girl may bequeath to her two brothers, as they are not heirs, while adhering to the one-third limit.