Do They Look Like Siblings?

So basically the male was being kicked and abused by my husbands workplace then he was chained up without food or water or shelter in the freezing rain. The pound was full and said theyd have to put him straight down because he's a pitbull. So my husband and I made a quick decision and took him to safety at our house. We let him loose and got the tight collar off his neck and he jumped in our arms crying and was so excited to go with us. There is only one pharoah hound breeder in my area and they look the same age. Grace is a pharoah hound pitbull mix and the breeder released her and her littermates to the pound or adopted them out because she was an accidental pregnancy. What I'm wondering is if this dog is her brother. They act exactly the same and look the same except his ears haven't fully perked up and he is slightly larger. The collar he has on is Graces ballgame collar. He needed something and everything else hurt him so I put the most loose collar I could on him. He has a horrible rash so I can't put him in her harness. He's a good boy. They love each other already. He had an accident and you should be seen his panic. I went to clean it up and he howled and whined and began to try to luck it up. I had to hug him to let him know I wasn't going to hurt him. Everytime I raise my hand to luck something up off a shelf he cries and cowers. He has done nothing but begged for me to hold him and curled up on my lap. I already have a dog and cat and guinea pig in my one bedroom apartment which is capacity for allowed animals. Idk what to do with him. Dogs can stay temporarily (about a month) but I need to get him healthy before I rehome him. How would you handle this? Grace is the last picture.