Need advice

My mom is getting evicted in 2 days and she wants me to take her dog. It’s a German Shepard female and I already have 2 males. (Also a German shepherd and pit bull). Although all dogs are fixed my 2 males will fight over her. We’ve had all dogs together before and they do play well but dominance comes into play with my males and they have fought. I have a 2 year old at home and I do not want him caught in the midst of them playing (all large dogs and they play rough) and potential fighting. She has no one else to take her and I do not want to see her go to a shelter.