I looked into the comments posted on Video. It went viral because kids thought she cried and was lonely (something that many teens have in common, and with many comments, likes and shares, it went viral). The video title said, "I hope this made her day better". So basically, he tricked her, and the Video cuts at the right time with clever video editing, giving a false sense to the viewer that he was kind to her. It is about pumping numbers to get sponsorship while exploiting people's personal lives. The Video is still up and counting. He could have taken it down, but fame is more important than helping a fellow person who is his grandma's age.
The battle for privacy was lost a long time ago :(