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.
If the heirs are only those mentioned in the question, and the deceased did not leave any other heir, then the people who inherit this deceased woman are only her father, her mother, her husband, her son and her daughter. As regards the other relatives whom you mentioned, they do not inherit as they are prevented by the existence of the father and the son. Your brother and two sisters from the father’s side do not inherit your mother as there is no cause of inheritance here because they do not have any blood relationship with your mother.
Therefore, the deceased’s mother gets one-sixth as her legal share, and her father gets one-sixth (as well) as his legal share due to the existence of direct heirs (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] Her husband gets one-fourth due to the existence of the children (direct heirs); Allaah Says (what means): {But if they have a child, for you is one fourth of what they leave, after any bequest they [may have] made or debt.}[Quran 4:12]
The remainder should be divided amongst the son and the daughter by Ta’seeb (by virtue of having a paternal relation with the deceased and not having an allotted share, so they get what is left after the allotted shares have been distributed); the male twice the share of the female as 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]
Therefore, the inheritance should be divided into 36 shares, the mother gets one-sixth, which is 6 shares, the father also gets one-sixth, which is 6 shares, and the husband gets one-fourth, which is 9 shares, the son gets 10 shares and the daughter gets 5 shares.
Finally, the two following matters should be mentioned:
1- The share of the deceased’s mother [i.e. the grandmother of the questioner] will be divided amongst her heirs, and the share of her father [i.e. the grandfather of the questioner] will be divided amongst his heirs. However, you did not clarify to us who their inheritors are so that we can tell you how the inheritance should be divided on them. Also, you and your sister do not inherit from your (maternal) grandfather and grandmother because the child of the daughter is not an heir.
2- With regard to the joint properties between the husband and the wife (your father and your mother), then the heirs of the wife are entitled to their right in her share in the property, and it should be divided amongst them as we already discussed above. The fact that the property is registered in the name of the husband does not impede you from inheriting. What is important is that the ownership should be proven by evidence or by the acknowledgement (the admission of the other party).
Allaah Knows best.