Why does an illegitimate child not inherit?

Q:

1. Why has an illegitimate child not been made a beneficiary of the wealth and money of his father, moreover he can't adopt his name, socially not an individual which other child can be. In spite of him being innocent, why has he been refused with all the bounties a child enjoys?

2. If his mother and father repent for their deeds, still the child will be facing all the hardships and trauma of not being a legitimate child. Would the father still be liable for his zina even after repenting? If not then how would the child be given justice for something which his parents did and he is being paying off?

Smoking weed

Q: Some youth in my community that I have caught smoking weed argue with me that they have done research, and found that weed has similar effects to coffee, it gives an energetic feeling with euphoria, similar to the effects coffee and energy drinks have to lots of people and thus the ruling of the Quran and hadith on it being an intoxicant like alcohol does not apply. How do I convince them otherwise?

Women going to the musjid

Q: I would like to inquire as to whether or not it is permissible for a male to teach women. At my local masjid, a sheikh gives a class and the women sit in the masjid. There is separation between the men and the women as they sit on opposite sides of the masjid. To me, this just doesn't feel right.

Moving away from a gathering where inappropriate things are being discussed

Q: If your family always talk about inappropriate things, that are hurtful and immodest and you do not like the atmosphere, how should you be as a person in this situation? Is it necessary that you must stay in the room, even when you do not like what is being said? Since you have to interact with your family, how long do you have to stay with them if they sit together for hours on end, if you are in this situation and you have other work to do too?