It's possible that:
* He's a private individual with no public acting experience.
* He might be using a different name for his acting credits.
* He might have worked on smaller, independent projects that are not easily searchable online.
To find more information, you might try searching for "Brent Triplett" on IMDB, a website dedicated to movie and TV credits. You could also search online using various keywords related to his potential profession (e.g., "Brent Triplett actor," "Brent Triplett film," etc.).