Amanda Bowman Gray, 40, from Heber City, Utah, shared a video of her two-year-old son Bo on Facebook earlier this week.
The clip shows Bo's older sister Lydia, 11, playing the popular song You Are My sunshine to the little boy, who sings along with her.
Bo, who has Down syndrome, has learned 12 words, all thanks to music
My daughter Lydia was watching Bo while I was in the shower. Came out to this. If she didn’t have a guitar I don’t know if she would know how to babysit him. This is her go to. It’s proof that music therapy works. Bo is 25 months old and has a 12 word vocabulary. Every word he has learned has been through music and singing. *If you would like to use this video it is now licensed with Storyful. All photos/stories are public on the page and do not need permission to be used, except this video. Thank you so much. https://storyful.com/
Posted by Amanda Bowman Gray on Monday, 15 January 2018
The video has now been watched a staggering 30 million times
Amanda and her husband Caleb, 26, are both musicians and started practicing the song a month before Bo needed heart surgery
Later on, Amanda and Caleb both performed the song to the little boy while he was recovering from the procedure and it is now his 'theme song'