My roommate is mean to his dog

Ok so I live with my boyfriend and my boyfriend’s friend. Let’s call him josh.. ok so josh just got a full German Shepherd about a month ago and he hasn’t walked the dog at all. He never once took him on a walk. Honestly I feel bad for the dog because he’s very energetic because he’s a puppy and he has no where to run or anything. We live in a townhouse so our backyard is very small. He can’t run around.

Idk what to do. I feel so bad for the dog. This is animal cruelty

Advice?