I'm going to wake up my flatmate in the morning
Is there a reason you want to wake them?
I'm tired of this guy's snoring.
Maybe you should let them sleep and when they get up get help for them for their issues. Its not nice to wake up someone in the middle of their sleep like that.
Nah man I'm going to tell him to stop snoring or I'm going to kill him.
That isn't the right way to help him with his snoring. You shouldn't wake him up, you should talk to him and see if he needs to see a doctor. You could get some earplugs in the meantime.