A son is a male offspring; a boy or man in relation to his parents.
Her husband gets one quarter. The remaining three quarters goes to the son and daughter who were alive when the woman died. Two shares for the son and one share for the daughter.
If the daughter had already passed away before her mother, the son will get the three quarters.
Muslim man is not allowed to permanently marry a Non Muslim woman from people of Book. Temporary marriage is permissible under some conditions.
Nikah is the recitation of the marriage agreement whether permanent or temporary which is must.
Assuming that your mother has passed, besides whether it is wajib for you or not, it would be the most noble and most loyal thing for you to do. Your mother might have forgotten, or unintentionally neglected, or gone through some difficulties, and did not perform her acts of worship.
You, the loyal son, are able to compensate that and the reward and blessings will not only go to her, but to you as well. In some hadiths it says there are some children who are loyal to their parents while alive, and not loyal when they die. Being not loyal is not doing dua or prayers or good deeds for them.
If you cannot roughly estimate, or have no idea, you have two options:
1. Pray what you can, as long as you are healthy and have time. The bonus is it's extra 'ibadah for you, which is a wonderful thing.
2. You can hire someone to do the 'ibadaat on behalf of your mother. There are many poor mu'mineen/mu'minaat who live off doing 'ibaadaat hire. Pay for whatever you are financially capable of.
With prayers for your success.
It is indeed very sad to hear that your late son took his life. May Allah ta'ala grant him ease in the Next life. Most important for you is not to ponder on why and how, but more on what you are able to do to contribute to helping others around you to avoid repetition of such an incident.
You experienced this, so you are able to help those around you and the community to bring about awareness. Take this unfortunate incident and use it for positive use. This will not only keep you occupied from having negative thoughts, or, God forbid, falling into depression, or losing hope in your life as well.
You should try to do righteous deeds and grant its reward to your late son. Do charity work on his behalf, and try to let others remember the good things about him, so they can be insired and learn from all of this.
Another thing that would be important to do is reach out to a qualified counselor who can give you professional tips to deal with such loss and overcome this difficulty.
With prayers for your success.
The eldest son is responsible to perform the obligatory Qadha prayers of his father if it was missed due to a valid reason like illness etc. If the parents did not perform their obligatory prayers for no valid reason, the Qadha is not obligatory on the eldest son. Although, it is very good for him or other children to pay for persons who perform Qadha prayers on behalf of deceased persons to perform the obligatory Qadha prayers of the deceased. This will help the deceased a lot.
Yes, there are many narrations in books of Hadeeth mentioning the reward for parents who have daughters and bring them up properly, that they will be in the Paradise.
Narrated from Imam Jafar Al-Sadiq (AS) : Daughters are reward while sons are a bounty, and reward will be for those who have daughters, while bounties will be asked about. (Al-Kaafi 6:6).
The believer is happy with what ever Allah (SWT) grants him, because Allah (SWT) knows the best for us, now and every time. Allah (SWT) grants to a couple only daughters or only sons or both, and does not give some couples any children, all because of His Wisdom and Mercy on us. (Sura 42, Verses 49 and 50).
Accepting and being satisfied with the will of Allah (SWT) is very important for he believers.
1. If the deceased left only one son and one daughter, and no wife, the daughter will inherit one third and the son wll inherit two thirds.
2. If the deceased left two sons and three daughters, and no wife, the wealth left must be divided in to seven equal parts, one part ( 1/7) for every daughter and two parts (2/7) for every son.
The son must tolerate and be patient and never counter his father or hurt his feelings. Whatever wrong done by any parent must be tolerated.
It is good to talk to your father either directly or indirectly to know the reasons of his attitude towards you. That might help decreasing the misunderstanding.
Elder son is responsible to perform of arrange performing Qadha of Salaah and fasting for his deceased father and mother. Either he performs or arranges for persons who perform on behalf of the deceased.
The wisdom behind rules of Islam is best known to Allah (SWT), His Prophet (SAWA) and The Infallible Imams (AS). We believe that all the rules from Allah (AS) are based on the absolute wisdom which aims to make our life real human life and guides us to the Right Path. We might be able to know some of the reasons but we can never argue for all the reasons.
Eldest son has the responsibly for the missed prayers and fasts of his parents because they served him before other children and he has the right to acquire special personal items (like rings, watch, personal Quran etc) from his deceased parents.
This rule does not mean that other children can not do that on behalf of their parents. In fact any of them can do whatever he or she wants to fulfill on behalf of their parents, but if it was not fulfilled, then the eldest son remains responsible to complete the remaining if any.
The son must obey and go to see his grandmother. The mother has no right to prevent her son from visiting his grand mother. No obedience to any one including parents in disobeying Allah ( SWT).
There is no difference in this regard between any of the grandchildren. As long as a child lives his or her children or the children of other siblings would not inherit.