My Cousin And I Are Taking Care Of My Nieces

My cousin and I are taking care of my nieces two dogs. She had to move to another area of the state for work. We've had them in our home in iowa for almost two years. We have 3 dogs of our own and 6 cats. (Big fenced yard and large house). All animals are rescues. Alfie is a dalmation mix, adopted from abusive and neglectful situation in NC. He bounced from one adopter to another til our niece found him. He normally has a funny goofy personality and is very friendly with us, but can be aggressive with other dogs. Always either in fenced yard with our other dogs or leashed when walking. He has history of intense fear of rain, storms, noises like garbage trucks, sirens, has chewed cords, destroyed a vacuum and ripped out window a/c. He has also tried to climb out of windows. However when we brought him into our home, those behaviors greatly diminished. He was fearful of fireworks etc which is common. Ate a few curtains and shredded a couple of doggy beds. But he has been tremendously more calm. Three days ago he wen suddenly back into intense fearful behavior. Shaking, sometimes wouldnt eat, hiding, tried to climb out windows, wouldn't go outside especially at night, and intensely reactive to loud noises. The physical signs we see are his right rear leg is somewhat stiff, and most of the time he cannot jump onto sofa or bed, which he usually does. He continues one behavior, licking his anal area. Please advise! Thank you!!