Hi, Alyssa! As a bulldog mom, my hunch is that your boyfriend's dog has some unresolved separation anxiety issues from your boyfriend leaving for a year and then coming back with a new, unfamiliar human. In my experience, bulldogs can be particularly possessive of their people and definitely know how to hold on to a grudge; when my little guy is feeling jealous or angry, he tends to make VERY intentional eye contact with us and then engage in a behavior he KNOWS is bad to communicate his dissatisfaction.

To second what Lisa said, it will likely take a lot of time, effort, and consistent training to try to resolve these behaviors. I would absolutely recommend consulting with a trainer in your area to discuss the dog's behavioral needs before you or someone else in the home is seriously injured. It's a sad reality that dogs cannot communicate their frustrations with us, and we're often left scratching our heads trying to understand why they are so upset! A great trainer will be able to provide insight and assistance with slowly building the dog's confidence and eliminating aggressive behaviors. Good luck!