The machine started, and was aimed to fire at the Meltan and fuse it with his child's Growlithe.
However the boy stopped this by jumping in front and kicking the Growlithe away. As a result the laser hit through him and then Silver, fusing them together.

The father's feeling didn't change whatsoever, and crushed the insect quickly and hastily. He had no remorse as insects weren't so important for his work.

Marc's voice echoed from the fusion to his father, but he refused to believe his very father had a change of heart.
He never acted like it so why should he believe it?