I don't know the content of Howie Mandel Ghost Stories well enough to determine their scariness. However, different people have different thresholds for being scared. Some might find any ghost story terrifying, while others might be more immune. If Howie Mandel draws on real - life - like situations and adds some unexpected twists in his stories, they could be quite spooky for a lot of people.
As we don't have a clear picture of Howie Mandel Ghost Stories, it's difficult to gauge their scariness. A good ghost story usually has elements like a creepy setting, strange characters, and an air of mystery. If his stories contain these elements and he can build up the tension effectively, then they could be scary. But his comedic background might lead him to play with the genre a bit, making them less conventionally scary and more of an entertaining blend of horror and humor.