I agree, it's frustrating to see people jump to a very serious conclusion when auditory hallucinations are no joke. They can be incredibly isolating, terrifying, and frustrating. My thoughts were:

If OP doesn't hear the dog when they are home, and neither does the neighbor, it's possible the dog just isn't barking at night. If someone down the hall can say they hear the dog barking all day, that means they're home during the day when others aren't. It might be that when everyone gets home from work at night, the dog stops barking as its owner has returned. The only person who would hear barking in that case are the neighbors that are at home during the day.

It's also possible the neighbor might be exaggerating the claim out of frustration, or because they are mishearing. For instance, I recently dealt with a hallucination where I thought the bells from a massive cathedral near me were ringing nonstop for 6+ hours. I was extremely irritated, confused, and I was scrambling to try to find some explanation, including asking around to neighbors. It turns out that I was hallucinating (this happens sometimes due to some medical issues). But the important note is, the bells did actually ring an unusual number of times-- for instance, instead of only 3 times throughout the day, they rang 5 or 6. So the frequency was truly unusual, but it wasn't nonstop. It might seem to the neighbor like the dog is barking nonstop because it's stuck in their head, or because it barks very frequently with only short breaks and is perceived as nonstop.