Three weeks later, the 9-year-old lost his father.
He's been searching for rainbows ever since.
Now, he doesn't have to look as hard because thousands of strangers from around the world have flooded the little boy with pictures of rainbows to comfort and console him.
"If I could hold out my arms and hug every single one of them, I would," his aunt, Crystal Skawinski, told CNN about the overwhelming response.
"The outpour is so heartwarming. Sometimes people leave me these messages where I want to break down and cry."
Robbie Ecuyer has autism. He's a big fan of Dora the Explorer, who in her cartoon exploits, crosses many bridges to finish her journeys -- including a rainbow one.
His mother, Shelly, battled cystic fibrosis for more than 10 years. His father died shortly afterward from a drug overdose.
Robbie now lives with his aunt in upstate New York.
Every time it rains, Robbie runs outside to look for a rainbow, remembering what his father told him.
One day, a rainbow didn't appear after a storm. Robbie was devastated.
So Skawinski reached out to friends through a Facebook post
, asking for photos of them.
Soon, photos started pouring in. Not just from friends, but from strangers all over the world. Thousands of them.
One woman shared this photo of a rainbow over the London Eye.
Another woman replied with a photo of a rainbow over the sea from a cruise ship headed to the Bahamas.
The post has reached Asia, where one man sent a photo of a double rainbow in Shanghai.
"My biggest thought is that my sister and my brother-in-law are shining down on my nephew, letting him know how loved he was," Skawinski said.
Some strangers, now turned friends, began reaching out -- each day -- to make sure Robbie was holding up OK.
"No one is ever alone," Skawinski said of the response. "There are so many good people out there. All these stories you hear out there and here comes Robbie with his little rainbow."