I thought the kid was fed up with the crummy storylines and hi-tailed it out of Dodge. I know I would have. Mr. Henesy started out as the main Damien Omen character, thus had a lofty part and mega dialogue. "When the moon rises...when the sun comes over the mountains...when the...oh, to heck with it."
I think David Collins was at his wickedest when he [spoiler]tried to kill his old man by removing the bleeder valve from the breaking system. And how about the time he locked Miss Winters up? And how about the crystal ball business when he declared all his relatives were about to die? What a kid.[/spoiler]
After playing such a mean spirited child, and then reduced to a mediocre ghost watcher, I'm sure DH's mama had no qualms about pulling the kid out of his contract, if indeed he had one.