Being possessed by a jin

Q: I have a question about jinn possession. Someone in my family is, I think possessed by a jinn. He has be showing the symptoms of jinn possession and I don't know what to do. I am his younger brother 16 years old and he is in his late 20s. He doesn't listen to dad and has arguments with him about Qur'an and Allah Ta'ala. Now he usually just stays in his room all day, sleeps, doesn't go to work, stares at things for periods at a time, and has bad mood swings. Please if there is any advice on what to do.

Wet dream

Q: When at night we see a wet dream and we ejaculate, is it farz to do gusl afterwards? In winters it is difficult to take bath at fajr and then go to masjid. If after ejaculation we don't do gusl can we offer salaah with just wudhu?