Try spraying the boyfriend with a water bottle!
I have four methods of disclipining my cat, they may help you:
1- Blowing on her face. Does no damage, and cats hate it.
2- Speaking sternly.
3- Shouting, loudly and angrily, while glaring.
4- Deliberately missing the cat with a well-thrown pillow.
Luckily, I’ve seldom had to employ these, and I never have to anymore, but they do get the point across, and the unwanted behavior soon stops.
Better still is to figure out why the cat is meowing, and remedy his complaint.
Is he bored? Some cats like television. Maybe you could arrange for the TV to come on at 6am. Are there windows he can look out of to watch the birds? That may help. A bird feeder outside the window may also help.
Is he lonely or insecure? Maybe the old “ticking clock in his bed” trick could work. Also, some cats like soothing music - smooth jazz is said to be a favorite.
Good luck. 
Maybe it’s not related to food. I’ve had cats that seemed to go into a meowing “Where is everybody?!?” panic, even when everybody was in the next room. The meow was very pitiful and plaintive. It was difficult to ignore.
So, Z, when the 6 a.m. mew ensues, where is Dewey? Can you reassure him that his humans, though sleeping, are still present and accounted for?
I became very adept at rousing from sleep just enough to say (in that sing-song, high pitched voice), “Miranda, we’re in here.”
Would Dewey be content to be “not-get-riddable” on the bed, or would he stomp around purring loudly and chewing your hair? I’ve had that, too.
I’m afraid to allow him on the bed for fear he’d be restless there and wake us up anyway, and I t hought it was probably easier to never ever allow him in bed with us than it would be to make him stop once he starts. He does have plenty of windows with places for him to sit on, and he loves watching the birdfeeder. When I do get up, he’s always soaking up the morning sun watching out the front windows. Just, at 6 AM, he wants to wake us up. From what I can tell there’s absolutely no reason for him to do so, except that he thinks it’s high time we were up. He’ll come into the bedroom from who knows where and start meowing at us. He knows we’re in there (sometimes Aaron gets fed up and snaps “Dewey! Shut up!”, so it’s not like he’s confused about which lumps are us. I never give the cat any attention when he meows because I can be consistent.) Maybe he’s just insecure.
He doesn’t really watch TV at all, but I can try to figure out if I can get the TV or a radio to turn on for him.