Is it permissible for us, the six brothers, while our father is still alive, to inherit from our deceased paternal aunt who has no children, and how is that done?

If the deceased's paternal aunt has no relatives other than those mentioned, then her inheritors are her brother and sister.

If they are full siblings or paternal siblings and are of the same degree, then the male receives twice the share of the female (your father and your sister), in accordance with the Almighty's saying: "And if there are brothers and sisters, male and female, then for the male is the share of two females."

If the brother is a full sibling and the sister is a paternal sibling, then the brother excludes the paternal sister.

If the sister is a full sibling and the brother is a paternal sibling, then the sister receives half by فرض (fixed share) according to the Almighty's saying: "If a man dies and has no child but has a sister, she will have half of what he leaves." The remainder goes to the paternal brother by تعصيب (residuary heirship), according to the Prophet's (peace be upon him) saying: "Give the prescribed shares to those entitled to them, and what remains is for the nearest male."

If they are maternal siblings, they both receive one-third equally, as stated in the Almighty's saying: "But if they are more than that, they share in one-third." The remainder goes to the nearest residuary heir.

The sons of the brother do not inherit because they are excluded by their father.

Finally, inheritances are a serious and complex matter and must be referred to the Sharia courts for investigation and to ensure that there are no wills, debts, or other rights taking precedence over the inheritors' rights.