I’ve heard about the rumors concerning members of the drowzee line and their penchant for leading children into dense woods for nefarious purposes, but rest assured that these are largely unfounded. (Most stories in which members of the drowzee line attack children are actually about the child wandering into a wild pokémon’s territory, prompting them to attack—if the story is true at all.)
When caught and tamed, most pokémon are relatively docile to their trainers. Even if they dislike being in captivity or if they dislike their specific trainer, pokémon rarely use force strong enough to kill, maim, or otherwise badly harm a human. This goes for psychics capable of hypnosis as well; there are very, very few stories of a tamed psychic pokémon turning their abilities onto their trainers without their consent. This is because most pokémon that allow themselves to be captured actually want to be captured, either because of curiosity, the need to be trained, or the want for companionship. Wild pokémon that don’t want to be captured are often too deep into the wilderness to be found, too strong to allow themselves to be captured, or will otherwise make their desires known before a poké ball touches them.
That having been said, it’s likely that the only thing you’ll want to worry about is your daughter’s drowzee occasionally putting her to sleep for fun, but so long as she isn’t in harm’s way when she does it (and her drowzee will likely also see to that), she should be fine.
The Pokédex According to Bill 