ANY time you get a new snake, even if it "looks" healthy, it should always be quarantined in a separate room if possible away from the healthies. Better safe than sorry, and it's a lot cheaper treating one RI in the long run, as opposed to one for each of your snakes :/
Good luck. I can't imagine being in your situation, and can only hope your family starts listening to you.
0.1 Normal Ball Python
1.0 Southern Black Racer (permanently disabled)
2.2 Cats
0.1 Dog
RESCUES I'VE FOUND HOMES FOR:
1.1 BCIs
2.1 Ball Pythons
1.0 Black Pastel Albino Ball Python