So many children just eat in front of the TV or gazing at phone or tablet, it isn't taught much these days, and certainly not in the schools my GC attend. When they come to us, they have learned to use knife and fork, (just about!), not to eat everything, even roast dinners, with their fingers. They don't eat with their mouths open, or speak with their mouths full, but it has taken some work, because it doesn't come naturally!
I don't think you can criticise a new boyfriend, most unwise, just hope DD eventually says something to him herself.