By Dana Kozlov

(CBS) — Imagine seeing your child being diagnosed with a illness one week to doctors recommending your child be institutionalized months later.

Parents of children with PANDAS disease say it happens, but one treatment can change everything.

“We were losing our son right in front of us,” Kate Drury says.

Her son Charlie was 8 when a strep throat diagnosis quickly became a mental health nightmare.

“He feared water. He wouldn’t touch it. He thought it would kill him,” Drury says.

Finally, after two months of doctor’s appointments and panic, Charlie was diagnosed with PANDAS disease, or Pediatric Autoimmune Neuropsychiatric Disorders Associated with Strep.

In a nutshell, Drury explains, the strep infection causes the immune system to attack the brain, often resulting in extreme, alarming and even harmful behaviors. One doctor recommended a high dose of antibiotics and IVIG, a costly injection not covered by insurance in which fresh blood antibodies are injected.

“Within two to almost six months it had fully reset his immune system,” the mother says.

Now 12, Charlie is thriving while Drury and another mother continue to fight for Charlie’s Law so that other families can better deal with devastating behavioral changes. Insurers would have to cover the treatment when recommended by physicians.

The bill overwhelmingly passed the state House and Senate last month. It now sits on Gov. Bruce Rauner’s desk and would be the first of its kind in the country.

PANDAS is still considered controversial in the medical community. The IVIG treatment can cost up to $15,000, Drury says.