Daniel Nico Laudit says he does not cry easily. He decided to test his mettle this month in a movie theater in Manila, and documented the experience for his 4.5 million followers on TikTok.

Before the screening, he filmed himself dancing and beaming and said to the camera: “Me before watching ‘How to Make Millions Before Grandma Dies.’” About two hours later, he uploaded a very different version of himself: wiping away the tears from his eyes in a bathroom.

“I went straight to the restroom after the movie because I wanted to cry out loud,” Mr. Laudit, 24, a content creator, said in a telephone interview. He said he cried some more when he got back home.

Reactions like Mr. Laudit’s have made the movie, which was filmed in Bangkok mostly in the Thai language, a runaway hit across Southeast Asia. In the Philippines, tickets were sold out on its opening day, theaters had to add more screenings to meet demand, and one chain started handing out tissues to viewers. In Singapore, it topped the box office from June 6-9. In Indonesia, it has drawn millions of viewers. In Thailand, it is the highest-grossing title of the year so far.

The plot revolves around an aimless and unemployed young man, M, whose sole ambition is to livestream his online games. He volunteers to take care of his maternal grandmother after he finds out she has Stage 4 cancer. His motivation is not filial piety; instead, he hopes that he can inherit her house.