Parents have to make some hard decisions when their child first starts dating. Are you going to be hands on or hands off? You know more about the world than they do, and you can spot warning signs they might miss.... But it's their life and they have to make mistakes so they'll learn. Whatever you decide to do, you're never going to be quite sure if it was the right thing.
That is, unless you daughter starts to flirt with a ghost. You can safely put your foot down on that shit.
Now, in this specific case, Casper is a sweet natured ghost, eager to please and polite. And this flirting is taking place in a PG rated movie about a boy who will always be about ten years old and a girl who is still in middle school, so nothing too risque is happening. Hell, the sentimental stuff is almost an afterthought. It isn't until after the rude ghosts have been tamed a bit and the human villains have been vanquished that Casper starts to get a little too friendly: right at the end of the movie a fairy godmother appears and grants Casper a three hour reprieve from death so he can dance with young Cat during her school's Halloween formal.
Up until this point Cat's dad does not have much of a parenting leg to stand on. He's dragged her around the country on pointless ghost hunting missions, he's endangered her by moving her into a house that actually is haunted, and he even accidentally killed himself while he was drunk. (Don't worry - he de-ghosted himself shortly thereafter, using a magical contraption in the basement of Casper's house. I have to say I envy him; my last basement just had a washing machine in it.) When Cat and her dad argue Cat is generally in the right...
But when Dad sees that Cat is dancing a few feet off the floor with a mysterious blond boy... Dude, you need to shut that shit down.
Overall, Casper is a surprisingly likeable movie. It gets around the morbidity of it's premise by having a light sense of humor - of course it has to acknowledge that Casper is the ghost of a small child, but once it gets his depressing backstory out of the way it spends most of it's time in more pleasant ways. It has a mixture of clever jokes (Dan Akryod shows up wearing a proton pack at one point), gross out gags that are probably only for kids (the bad ghosts have a very immature idea of what being bad is), and there's a lot of sweet-natured family-comedy, too.
Just when you think it's going to avoid all the landmines, it steps on one right at the end. Casper has been trying to pal around with Cat for the whole movie, and it makes sense - he's lonely; he's been without a real family for a long time. His interest in her can border on the uncomfortable - at one point he watches her sleep (!) - but it's easy enough to walk back from that, because his interest is more about talking about what life feels like to someone who happens to be alive than it is talking with her about her specific life. His solemnity dissolves the tension a bit - there are times he seems more like a dog than a boy, when he seems perfectly content just to sleep at the foot of the bed.
But that last scene, where Cat and a rejuvinated Casper dance! That takes a relationship that needs to be platonic and makes it romantic - and maudlin to boot, since Casper's fairy tale ending is only for one night. There's just so much wrong with it. For one, mismatched love never works out, and dead / alive is sort of the ultimate mismatch. Plus Cat is way too young to be living with her boyfriend, and Casper is permanently a fixture in the house. And by permanently, I mean: for over a hundred years already, with another hundred in front of him, too. Which reminds me: there's a hellacious age gap. This has bad idea written all over it.
Seriously, Dad: it's time to lay down the law: no holding hands with Casper, no sweet pillow talk either. And remember: her punishment can't be a grounding, because her would-be beau has been kicking around her room since Teddy Roosevelt times. You un-deaded yourself for a reason, Dad, and I honestly think that reason was to tell Casper he should maybe be a little less friendly. Because yeah, he looks cute now, but if you don't get a bit hands on now and guide her right - well, who knows? She could end up making pottery with a Patrick Swayze type, and then you're fucked, boy-o.