Preventing one's father from committing sin

Q: My father is committing a major sin. I have known this for a very long time but I don't know what to do as I am only 13 years old. If I tell him then I'm scared of my family going into pieces. This is not the first time because he has been caught before before and he says that he has stopped but I am the only person who knows that he hasn't stopped this sin. My father was the nicest person ever until he started this sin. He still is loving and caring but he still commits a very bad sin.

Speaking to a non-mahram

Q: I have come across a sister who is Alhamdullilah very nice and has good knowledge about Islam and even practices a lot. She loves me a lot and I too love her for the sake of Allah. I met her 4 months ago. But now the problem I am having is that she talks too much and I get irritated.

Everyday she calls me and talks for 2 hours. Each and every day she calls. If I am busy and I can't receive the phone she will continously call 15 to 20 times. I am quite an introvert person and I dont like to talk much. She says that I have to be an extrovert to call people to Islam. I Have to be open and talk to people.

I love her but this is something that is really irritating me a lot. She usually talks about Islam and Hadith but sometimes too much talking also leads to gossip and useless talks. I am not able to understand how to get rid of this. Can you help me from any hadaith or Quran which I can relate to her.

Is it not wrong to talk so much whether its useless or about Deen. I can't explain how much its irritating me. Should I cut off with her? If I switch off my phone she calls my brother.