Mom's Got a Date with a Vampire (2000) on Netflix

Plot summary

Thirteen-year-old Adam Hansen and Duffy, his best friend, have tickets to a Headless Horseman concert, and Adam's older sister Chelsea, who is sixteen, has a date with her boyfriend Peter. Both are grounded: Adam for skipping his homework and inventing a story from an article in The Weekly Secret, Chelsea for calling him a dweeb. Their mother Lynette is divorced and watches over their eight-year-old brother Taylor. For Adam and Chelsea to keep their plans, Lynette has to leave the house, so they arrange a meeting with a mysterious man named Dimitri. Taylor, however, catches sight of Dimitri changing into a bat and is convinced the stranger is a vampire.