(Meredith) – A touching video of a toddler singing with his big sister shows the power of music therapy.

Amanda Bowman Gray shared a video on Facebook of her children singing “You are my Sunshine” on Monday, and it already has 37 million views.

Gray said her 2-year-old son, Bo, has Down syndrome and a long list of medical ailments.

When she heard the little guy and his big sis, Lydia, singing their heartfelt duet she had to record it.

The mom said she and her husband, who are both musicians, routinely sang “You are my Sunshine” to Bo when he was in the hospital for heart surgery. Since then, it’s become his theme song.

Click here to watch the featured Facebook video. 

Gray said her son has a 12-word vocabulary but learned them all, thanks to music therapy.

 “It’s proof that music therapy works,” she wrote. “Every word he has learned has been through music and singing.”

The video she shared showing her children singing warmed many hearts on social media.

“I’m not crying, you’re crying,” one commenter wrote.

Gray said Bo is “seriously our little miracle.”

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