Final answer:
Henry can establish trustworthiness and credibility by showcasing his character and qualifications, such as education, job, community involvement, and research on the subject matter.
Step-by-step explanation:
To establish trustworthiness and credibility, Henry can showcase his character and qualifications. This can be done by highlighting his education, job, community involvement as a parent, and research on the subject matter. By referring to his personal experiences and expertise, Henry establishes himself as a credible source. For example, he can mention his extensive research on the topic, his relevant education, or his involvement in the community as a concerned resident.