This story is priceless. We found a mother mouse and her babies in the dress up clothing box of our preschool once, and mom took all the babies but one, never came back for the runt so I took her home. Named Squeak, lol. She died loved. Bless you for caring (rabbits in the wild (or not) can develop a parasite called E. Cuniculi (head tilt), which very much sounds like Javi's left side weakness. There are antibiotics for rabbits but it sounds like you've gotten Javi stabilized, well done!