The concerned mum took Kian to see a therapist, who suggested he be tested for ADHD, before Yazdani read an article about the condition which linked it to the way children sleep.
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She wrote: "Children should not breathe through their mouths. Not while awake, not while asleep. Never.
"Mouth breathing is not normal and has long term consequences for health. I'll repeat, because this is important – mouth breathing is not normal, not during the day or at night.
"When a child breathes through their mouth, their brain [and body] is not getting enough oxygen. At night, this lowered oxygen saturation is detrimental to the quality of sleep and their brain's ability to get enough rest."
Yazdani explained that sleep deprivation in children and ADHD have the "exact same symptoms".
Little Kian was then diagnosed with sleep apnea and sinusitis, before surgery to remove his tonsils and adenoids transformed their lives.
"We have seen a complete 180 in behaviour," she wrote. "Here's why I am sharing: No one, in my 12 years of parenting, ever told me any of this. All the signs were there, right in front of our eyes, and I had no clue."