We were strongly warned not to bring up to parents their child may have autism, ADHD or be using certain substances

Or have some type of mental condition. It was frustrating trying to drop subtle hints, and the parents didn't understand. I had students I felt strongly needed help, and I couldn't help them get it.
I remember two sisters who pretty obviously had ADD or some focus issue. But, they weren't hyperactive. They were quiet and didn't disrupt class so the parents didn't notice. But, they couldn't concentrate for more than a few seconds so were doing poorly in their classes. A special ed teacher who was team teaching with me thought they had it as well. But, we weren't allowed to tell the parents we thought they should talk to their doctor about it.