What should I do with the money inherited from my paternal aunt if I am unable to reach her full siblings, who are the rightful heirs, after extensive attempts?

If it is established that the brothers inherit from her, then the share of the missing heir is reserved for him and not disposed of. If they despair of finding him, his share is given as charity on his behalf. If some heirs acknowledge the lineage of a person while others deny it, then the lineage is not legally established. However, the person acknowledged inherits only from the share of those who acknowledged him.