Get some tissues. No, really. Do it.

San Antonio couple Samir and Stephanie Deais recently filmed their son, Alexander, singing "Remember Me" from the Disney film, "Coco," to an altar dedicated to his late baby sister, Ava Lynn, on what would have been her first birthday.

The Deais family told that their daughter was born with hydronephrosis, a kidney ailment, and died last May at 4 months old. 

Samir Deais said the film, about Dia de Los Muertos, helped their 4-year-old son deal with the death. 

"I couldn't be more thankful for the movie," Deais said to "It's made it so easy to understand for him and for us to explain to him in a beautiful way."  

My son singing "Remember Me" from the movie "Coco" to his baby sister, Ava, who we lost this past May.

He's only 4 years old and he understands. He didn't even know he was being recorded. He just wanted to sing to her for her 1st birthday!

Happy Birthday mamas, we miss you!