Autism - Mom in denial

I work in the youngest room for 2/3 year olds, one 2.5yo girl started with us in August. All of us staff think it’s clear she has Autism or some other disability.

She is completely non verbal but makes noises and mimics sounds, flinches at noise and touch like it hurts her, has meltdowns where she screams the loudest screams I’ve ever heard and is heard throughout the entire building. If we offer her anything like water or food she pushes it away and yells at us, even if the water/food is still on the table for the others she goes out of her way to push it away and gets very upset that it’s still in sight, so she barely eats and drinks except bread and throws most of it on the floor. She’s constantly climbing, opening everything, and wandering off in her own world. She doesn’t follow any commands or rules all the other children have to follow and can be a battle to get her to do basic things like sitting at lunch, staying in circle time, laying down at nap time unless she wants to do those things.

She has an obsession with trying on clothes, we often find her wearing staff and other children’s shoes and any other clothing she manages to grab. Also has a thing for getting under carpets and mattresses, and putting blankets and other big pieces of fabric on her head and walking around.

HERE’S THE ISSUE: Her mother, who happens to work at our nursery as a special ed worker working with a non verbal autistic child, completely denies the possibility of her having autism and needing any special treatment/help. When we tried to get her started with a diagnosis, her mom wrote a long essay on why her daughter couldn’t possibly have autism, which mostly included a long list of the “words” she had said. She hasn’t said a single word the whole time she’s been in our care and her mom takes the random sounds she makes as words due to strong denial. Due to this we have no way of giving her the help she needs and can sue us if we give her ANY special help. This is exhausting all the staff as we are often missing some workers and struggle with caring for the whole group, on top of that we have to somehow be able to watch her 24/7 and get her to calm down from her meltdowns, AND then calm the other children down because her screams hurts their ears and makes everyone upset.

What the hell are we meant to do here?? This is wrong for everyone involved especially the child that’s not getting the full help she needs. Everyone is upset and overwhelmed and we’re just stuck in this situation.