Aiding in Sin

Providing the internet to someone who uses it for lawful and unlawful purposes

Q: What is the ruling on providing the internet to someone who uses it for lawful and unlawful purposes, given that some liken it to renting a house for a disobedient Muslim or an infidel? Is this true? What is the response to this comparison? Is there any doubt about the matter? Please clarify, as the matter concerns my parents. If there is any doubt about it, is it more important to obey one's parents?

Selling an item to someone not knowing whether they will use it for something impermissible

Q: 

1. Would it be halal for me to sell gold to a cash for gold place because there is a high chance they will sell this gold to a refiner, scrap gold buyer or so on and they might use this gold to make gold jewellery for men etc.? 

2. What about selling grapes to a business that sell grape related products so the grapes I sell to them can be used to make their grape juice or it can be used for their wine etc. Will the income be haram? Because I’m unsure what they will use it for.

Transporting a non married couple to their home

Q: An old school friend that does not practice deen (I don‘t exactly know his belief) and his girlfriend (I think she might be Christian since we are in Germany and she’s German) went to another country for holidays.

Now they want me to pick them up from the airport and bring them to their home where they live together. Since I don‘t want to be sinful I would like to know if it was haram for me to transport these people.

I read that transporting people to certain places as a taxi driver is makruh tanzihi in the Hanafi madhab since one is only indirectly assisting in sin. However, I am not a taxi driver and I don‘t want to make assumptions.

Am I sinful for transporting non married couples to their home?

Advising people to refrain from committing haraam

Q: Am I sinful if I see a family or friend saying or doing something haraam and I don't denounce it. Ever since I found this out, I have been telling people so politely but now I keep spotting things and because I keep denouncing things, I lost so many friends in the past as they find me annoying and it makes my life miserable. Is denouncing a sin in my heart efficient or am I sinful if I don't say anything?

Getting sin for inviting people towards wrong

Q: If a Muslim has a group of Muslim friends. The man knows zina is haram. His friends dont know zina is haram. The man invites them to commit zina. They all go and commit zina. The man doesn't commit zina.

1. Will the man be getting their sin of zina or he wont be getting their sin of zina since the friends were unaware of the act being haram?

2. Is the man guilty of kufr because his friends did not know zina is haram and they thought it was halal and committed it. (Thinking a haram act as halal and doing it is kufr).