Procedure for a female taking bay'at

Q: I want to change my life and attain closeness to Allah and true love for Him. However my parents don't want me to take bay'at. They think I'll become "too pious". So can I take bay'at without my parents permission? I won't be corresponding with the Sheikh directly but rather with his wife. And I know that the Sheikh is a Sheikh-e-Kaamil.

Embracing Islam secretly

Q: I have a friend and she is really inspired by me and my religion. I am a Muslim. I told her about the importance of Islam and why she should embrace. She looked convinced but all of a sudden she said that she will get family pressure if she embraces Islam openly. I told her to convert her heart as Allah sees whats in the heart. She has accepted Allah as God and Muhammad (sallallahu alaihi wasallam) as the last prophet. Is this allowed? Will she still see hell?.I hope she sees jannah. I dont want her to go in hell. I want every friend of mine to join me in jannah. 

Taking a false oath when dealing with a psychological patient

Q: Our elder brother is a physiological patient and on drug abuse. We tried to convince him for treatment but he refused. We started an outdoor treatment with a physiologist. In this treatment we teamed up with the psychologist and started his physiological treatment in which we perform different types of therapies. We changed our behaviour towards him and made different approaches. He is almost 75% recovered now.

Recently he started doubting us that we are doing some kind of treatment without him knowing. He started fighting with us and we denied doing any treatment as the doctor told us not to tell him at this stage. He is now asking us to put our hand on the Quran and take an oath that we are not doing any treatment for him. The doctor is advising us that after a few months, when he is fully recovered, then only should we will tell him the truth.

What does Islam say? Should we take a false oath to satisfy him for sake of his recovery and later, when he is fine then tell him the truth?