I think my dads cheating on my mother:(?

I am so scared because my dads been saying that he has been going to his friends house and he is known guy we went to Los angles this weekend and he wanted to leave really early like he said we are only 2 days only! and I'm like okay then he keeps nagging on my mom and she nags back. the night before we leave i find out hes drunk and its against our religion im Muslim and he smells like whiskey! and is it true that some cigars have scent of whiscky? I am really really really sad and my lifes goign doiwn hill is what i feel and i cant takeee it anymore :( Pleasee help me out and i really canttt calm down and i called him an hour ago he answerednow its offf how can i find out if he is cheating?