All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad is His slave and Messenger.
First of all, please accept our condolences on the death of your husband and we ask Allaah to have mercy upon him, forgive him and be pleased with him.
You should know that the brothers and sisters of the deceased do not inherit in case of the existence of the father and the children, because the father and the children prevent others from the inheritance as they are directly related to the deceased.
Therefore, if the heirs are only those mentioned in the question, then the share of both wives is one-eighth because of the existence of the children as Allaah Says (what means): {But if you leave a child, then for them is an eighth of what you leave.}[Quran 4:12] So, the two wives divide amongst them this one-eighth.
The share of the father and the mother is one-sixth for each of them because of the existence of the children; Allaah Says (what means): {And for one’s parents, to each one of them is a sixth of his estate if he left children.}[Quran 4:11] The remainder should be divided among the children, the male twice the share of the female; Allaah Says (what means): {Allaah instructs you concerning your children [i.e. their portions of inheritance]: for the male, what is equal to the share of two females.}[Quran 4:11]
In which case, after paying off the debts and bequests (of the deceased), the inheritance should be divided into 240 shares, each parent gets 40 shares, each wife gets 15 shares, and the remainder should be divided amongst the children; the male twice the share of the female, which is that each son gets 52 shares each, and the daughter gets 26 shares.
Finally, it should be noted that the matter of inheritance is very complex an issue, so a mere Fatwa which is an answer issued according to the question is not enough. Rather, the matter should be taken to an Islamic court to study the case carefully.
Allaah Knows best.